Condensed Matter
New submissions
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New submissions for Thu, 22 Aug 19
 [1] arXiv:1908.07513 [pdf]

Title: Heterobilayers of 2Dmaterials as a platform for excitonic superfluidityComments: 5 figureSubjects: Mesoscale and Nanoscale Physics (condmat.meshall); Materials Science (condmat.mtrlsci); Quantum Gases (condmat.quantgas); Computational Physics (physics.compph)
Excitonic condensate has been a phase longsought within bulk indirectgap semiconductors, quantum wells, and 2D material layers, all tried as carrying media. Here we propose intrinsically stable 2D semiconductor heterostructures with doublyindirect overlapping bands as optimal material platforms for realizing excitonic condensation. After screening a list of exfoliable 2D materials, we identify several pairs as candidate heterostructures where spontaneous excitonic condensation mediated by purely electronic interaction should occur. Unlike other singlelayered systems, where excitonic condensation may be hampered by the Peierls instability, these heterobilayers retain stable phonon spectra while offering nearoptimal carrier density. Different parts of the electronhole phase diagram, including BECBCS crossover, can be accessed through inplane strain, external electric field, or changing interlayer distance, with exciting applications in superfluid transport, Josephsonlike tunneling, and dissipationless charge counterflow.
 [2] arXiv:1908.07515 [pdf]

Title: Direct and inverse spin Hall effect: Lorentz force and Zeeman energyComments: 3 pages main body, 3 figures, 1 page supplementary informationSubjects: Mesoscale and Nanoscale Physics (condmat.meshall)
It is shown that magnetic forces as the Lorentz force, exerted on electric currents, and the force {\mu}Div(B), exerted on electron spins at rest, account for both the transverse spin imbalance typical of spin Hall effect and the transverse charge imbalance associated with pure spin currents (inverse spin Hall effect). Considering that for stationary currents the laboratory reference frame and those for which the spin up and spin down carriers are at rest are inertial systems, one can easily find the forces exerted by the lattice on both spin subbands, as well as the force between subbands.
 [3] arXiv:1908.07530 [pdf, other]

Title: Prethermal Phases of Nonequilibrium Matter in Longrange Interacting SystemsAuthors: Francisco Machado, Dominic V. Else, Gregory D. KahanamokuMeyer, Chetan Nayak, Norman Y. YaoComments: 18 pages + 12 pages appendicesSubjects: Statistical Mechanics (condmat.statmech); Disordered Systems and Neural Networks (condmat.disnn); Quantum Gases (condmat.quantgas); Strongly Correlated Electrons (condmat.strel); Quantum Physics (quantph)
We prove the existence of nonequilibrium phases of matter in the prethermal regime of periodicallydriven, longrange interacting systems, with powerlaw exponent $\alpha > d$, where $d$ is the dimensionality of the system. In this context, we predict the existence of a disorderfree, prethermal discrete time crystal in one dimension  a phase strictly forbidden in the absence of longrange interactions. Finally, using a combination of analytic and numerical methods, we highlight key experimentally observable differences between such a prethermal time crystal and its manybody localized counterpart.
 [4] arXiv:1908.07545 [pdf, other]

Title: Isometric Tensor Network representation of stringnet liquidsAuthors: Tomohiro Soejima, Karthik Siva, Nick Bultinck, Shubhayu Chatterjee, Frank Pollmann, Michael P. ZaletelComments: 20 pages, 22 figuresSubjects: Strongly Correlated Electrons (condmat.strel); Quantum Physics (quantph)
Recently, a class of tensor networks called isometric tensor network states (isoTNS) was proposed which generalizes the canonical form of matrix product states to tensor networks in higher dimensions. While this ansatz allows for efficient numerical computations, it remained unclear which phases admit an isoTNS representation. In this work, we show that twodimensional stringnet liquids, which represent a wide variety of topological phases including discrete gauge theories, admit an exact isoTNS representation. We further show that the isometric form can be preserved after applying a finite depth local quantum circuit. Taken together, these results show that longrange entanglement by itself is not an obstruction to isoTNS representation and suggest that all twodimensional gapped phases with gappable edges admit an isoTNS representation.
 [5] arXiv:1908.07548 [pdf]

Title: Ta, Ti and Hf effects on Nb$_3$Sn highfield performance: temperaturedependent dopant occupancy and failure of Kramer extrapolationAuthors: Chiara Tarantini, Shreyas Balachandran, Steve M Heald, Peter J Lee, Nawaraj Paudel, Eun Sang Choi, William L. Starch, David C LarbalestierComments: 9 pages, 10 figuresSubjects: Superconductivity (condmat.suprcon); Materials Science (condmat.mtrlsci)
The increasing demand for improving the highfield (1622 T) performance of Nb$_3$Sn conductors requires a better understanding of the properties of modern wires much closer to irreversibility field, H$_{Irr}$. In this study we investigated the impact of Ta, Ti and Hf doping on the highfield pinning properties, the upper critical field, H$_{c2}$, and H$_{Irr}$. We found that the pinning force curves of commercial Ti and Ta doped wires at different temperatures do not scale and that the Kramer extrapolation, typically used by magnet designers to estimate highfield critical current density and magnet operational margins from lower field data, is not reliable and significantly overestimates the actual H$_{Irr}$. In contrast, new laboratory scale conductors made with NbTaHf alloy have improved highfield J$_c$ performance and, despite contributions by both grain boundary and point defect pinning mechanisms, have more predictable highfield behavior. Using Extended Xray Absorption Fine Structure spectroscopy, EXAFS, we found that for the commercial Ta and Ti doped conductors, the Ta site occupancy in the A15 structure gradually changes with the heat treatment temperature whereas Ti is always located on the Nb site with clear consequences for H$_{c2}$. This work reveals the still limited understanding of what determines H$_{c2}$, H$_{Irr}$ and the highfield J$_c$ performance of Nb$_3$Sn and the complexity of optimizing these conductors so that they can reach their full potential for highfield applications.
 [6] arXiv:1908.07575 [pdf, other]

Title: Sparse sampling approach to efficient ab initio calculations at finite temperatureComments: 13 pages, 8 figuresSubjects: Strongly Correlated Electrons (condmat.strel); Computational Physics (physics.compph)
Efficient ab initio calculations of correlated materials at finite temperature require compact representations of the Green's functions both in imaginary time and Matsubara frequency. In this paper, we introduce a general procedure which generates sparse sampling points in time and frequency from compact orthogonal basis representations, such as Chebyshev polynomials and intermediate representation (IR) basis functions. These sampling points accurately resolve the information contained in the Green's function, and efficient transforms between different representations are formulated with minimal loss of information. As a demonstration, we apply the sparse sampling scheme to diagrammatic $GW$ and GF2 calculations of a hydrogen chain, of noble gas atoms and of a silicon crystal.
 [7] arXiv:1908.07579 [pdf, other]

Title: Multiple Andreev reflections and Shapiro steps in a GeSi nanowire Josephson junctionAuthors: Joost Ridderbos, Matthias Brauns, Ang Li, Erik P. A. M. Bakkers, Alexander Brinkman, Wilfred G. van der Wiel, Floris A. ZwanenburgJournalref: Phys. Rev. Materials 3, 084803 (2019)Subjects: Mesoscale and Nanoscale Physics (condmat.meshall); Quantum Physics (quantph)
We present a Josephson junction based on a GeSi coreshell nanowire with transparent superconducting Al contacts, a building block which could be of considerable interest for investigating Majorana bound states, superconducting qubits and Andreev (spin) qubits. We demonstrate the dc Josephson effect in the form of a finite supercurrent through the junction, and establish the ac Josephson effect by showing up to 23 Shapiro steps. We observe multiple Andreev reflections up to the sixth order, indicating that charges can scatter elastically many times inside our junction, and that our interfaces between superconductor and semiconductor are transparent and have low disorder.
 [8] arXiv:1908.07580 [pdf, ps, other]

Title: Magic highorder harmonics from a quasionedimensional hexagonal solidComments: 16 pages, Four figures, 2 TablesJournalref: Physical Review B, Volume 99, 094313 (2019)Subjects: Materials Science (condmat.mtrlsci); Strongly Correlated Electrons (condmat.strel)
Highorder harmonic generation (HHG) from atoms is a coherent light source that opens up attosecond physics, but it is the application of HHG to solids that brings much of excitement for the last decade. Here we report a completely new kind of harmonics in a quasionedimensional and hexagonal barium titanium sulfide: Under circularly polarized laser excitation, harmonics are generated only at first, fifth, seventh and eleventh orders. These magic harmonics appear only with circularly polarized light, not with linearly polarized light. Neither cubic nor tetragonal cells have magic harmonics even with circularly polarized light. Through a careful grouptheory analysis, we find that two subgroups of symmetry operations unique to the hexagonal symmetry cancel out third and ninth harmonics. This feature presents a rare opportunity to develop HHG into a crystalstructure characterization tool for phase transitions between hexagonal and nonhexagonal structures.
 [9] arXiv:1908.07594 [pdf, other]

Title: Chaotic wave packet spreading in twodimensional disordered nonlinear latticesComments: 15 pages, 5 figuresSubjects: Disordered Systems and Neural Networks (condmat.disnn); Statistical Mechanics (condmat.statmech); Chaotic Dynamics (nlin.CD); Computational Physics (physics.compph)
We reveal the generic characteristics of wave packet delocalization in twodimensional nonlinear disordered lattices by performing extensive numerical simulations in two basic disordered models: the KleinGordon system and the discrete nonlinear Schr\"{o}dinger equation. We find that in both models (a) the wave packet's second moment asymptotically evolves as $t^{a_m}$ with $a_m \approx 1/5$ ($1/3$) for the weak (strong) chaos dynamical regime, in agreement with previous theoretical predictions~\cite{F10}, (b) chaos persists, but its strength decreases in time $t$ since the finite time maximum Lyapunov exponent $\Lambda$ decays as $\Lambda \propto t^{\alpha_{\Lambda}}$, with $\alpha_{\Lambda} \approx 0.37$ ($0.46$) for the weak (strong) chaos case, and (c) the deviation vector distributions show the wandering of localized chaotic seeds in the lattice's excited part, which induces the wave packet's thermalization. We also propose a dimensionindependent scaling between the wave packet's spreading and chaoticity, which allows the prediction of the obtained $\alpha_{\Lambda}$ values.
 [10] arXiv:1908.07601 [pdf, ps, other]

Title: Novel Fracton Phases from Gauge TheoriesComments: 13 pages, 12 figuresSubjects: Strongly Correlated Electrons (condmat.strel); High Energy Physics  Theory (hepth)
We introduce new models of fracton order based on $\mathbb{Z}_2$ lattice gauge theories in $d=2$ and $d=3$ spatial dimensions. In the $3d$ models, the ground state degeneracy grows exponentially with the square of the linear size of the system at the same time as it exhibits a dependence on the topology of the underlying manifold. Also, there are completely mobile gauge charges living along with immobile fractons. Until now most fracton models were obtained from a process of gauging subsystem symmetries of some generalized Abelian lattice gauge theories, and our method shows that fracton phases are also present in more usual lattice gauge theories. We also show how to construct fracton models from lattice gauge theories with arbitrary, possibly nonAbelian finite gauge groups and as examples, we study fracton models obtained from choosing $\mathbb{Z}_3$ and $S_3$ as gauge groups.
 [11] arXiv:1908.07606 [pdf, ps, other]

Title: Vortex Shear Banding Transitions in Superconductors with Inhomogeneous Pinning ArraysComments: 14 pages, 11 figuresSubjects: Superconductivity (condmat.suprcon); Soft Condensed Matter (condmat.soft)
We numerically examine the flow of superconducting vortices in samples containing square pinning arrays in which a band of pins is removed. When a drive is applied at an angle with respect to the band orientation, we find that the vortex depinning initiates in the pinfree channel. The moving vortices form a series of quasionedimensional shear bands that begin flowing in the bulk of the pinfree channel, and the motion gradually approaches the edge of the pinned region. The consecutive depinning of each shear band appears as a series of jumps in the velocityforce curves and as sharp steps in the spatial velocity profiles. When a constant drive is applied parallel to the pinfree channel along with a gradually increasing perpendicular drive, the net vortex velocity decreases in a series of steps that correspond to the immobilization of bands of vortices, and in some cases the flow can drop to zero, creating a field effect transistor phenomenon. These results should also be relevant to other types of systems that exhibit depinning in the presence of inhomogeneous pinning.
 [12] arXiv:1908.07609 [pdf]

Title: Persistent, rewritable frequency tuning of a nanoelectromechanical resonator using photoinduced dopingComments: 19 pages, 4 figuresSubjects: Mesoscale and Nanoscale Physics (condmat.meshall); Applied Physics (physics.appph)
Tuning the frequency of a resonant element is of vital importance in both the macroscopic world, such as when tuning a musical instrument, as well as at the nanoscale. In particular, precisely controlling the resonance frequency of isolated nanoelectromechanical resonators (NEMS) has enabled innovations such as tunable mechanical filtering and mixing as well as commercial technologies such as robust timing oscillators. Much like their electronic device counterparts, the potential of NEMS grows when they are built up into largescale arrays. Such arrays have enabled neutralparticle mass spectroscopy and have been proposed for ultralowpower alternatives to traditional analog electronics as well as nanomechanical information technologies like memory, logic, and computing. A fundamental challenge to these applications is to precisely tune the vibrational frequency and coupling of all resonators in the array, since traditional tuning methods, like patterned electrostatic gating or dielectric tuning, become intractable when devices are densely packed. Here, we demonstrate a persistent, rewritable, scalable, and highspeed frequency tuning method for graphenebased NEMS. Our method uses a focused laser and two shared electrical contacts to photodope individual resonators by simultaneously applying optical and electrostatic fields. After the fields are removed, the trapped charge created by this process persists and applies a local electrostatic tension to the resonators, tuning their frequencies. By providing a facile means to locally address the strain of a NEMS resonator, this approach lays the groundwork for fully programmable largescale NEMS lattices and networks.
 [13] arXiv:1908.07612 [pdf, other]

Title: Accessing temperature waves: a dispersion relation perspectiveSubjects: Mesoscale and Nanoscale Physics (condmat.meshall)
In order to account for nonFourier heat transport, occurring on short time and length scales, the oftenpraised DualPhaseLag (DPL) model was conceived, introducing a causality relation between the onset of heat flux and the temperature gradient. The most prominent aspect of the firstorder DPL model is the prediction of wavelike temperature propagation, the detection of which still remains elusive. Among the challenges to make further progress is the capability to disentangle the intertwining of the parameters affecting wavelike behaviour. This work contributes to the quest, providing a straightforward, easytoadopt, analytical mean to inspect the optimal conditions to observe temperature wave oscillations. The complexvalued dispersion relation for the temperature scalar field is investigated for the case of a localised temperature pulse in space, and for the case of a forced temperature oscillation in time. A modal quality factor is introduced showing that, for the case of the temperature gradient preceding the heat flux, the material acts as a bandpass filter for the temperature wave. The bandpass filter characteristics are accessed in terms of the relevant delay times entering the DPL model. The optimal region in parameters space is discussed in a variety of systems, covering nine and twelve decades in space and timescale respectively. The here presented approach is of interest for the design of nanoscale thermal devices operating on ultrafast and ultrashort time scales, a scenario here addressed for the case of quantum materials and graphite.
 [14] arXiv:1908.07628 [pdf, other]

Title: A linearscaling algorithm for rapid computation of inelastic transitions in the presence of multiple electron scatteringComments: 10 pages, 5 figures, 2 tablesSubjects: Materials Science (condmat.mtrlsci); Computational Physics (physics.compph)
Strong multiple scattering of the probe in scanning transmission electron microscopy (STEM) means image simulations are usually required for quantitative interpretation and analysis of elemental maps produced by electron energyloss spectroscopy (EELS). These simulations require a full quantummechanical treatment of multiple scattering of the electron beam, both before and after a corelevel inelastic transition. Current algorithms scale quadratically and can take up to a week to calculate on desktop machines even for simple crystal unit cells and do not scale well to the nanoscale heterogeneous systems that are often of interest to materials science researchers. We introduce an algorithm with linear scaling that typically results in an order of magnitude reduction in compute time for these calculations without introducing additional error and discuss approximations that further improve computational scaling for larger scale objects with modest penalties in calculation error. We demonstrate these speedups by calculating the atomic resolution STEMEELS map using the Ledge transition of Fe, for of a nanoparticle 80 \AA\ in diameter in 16 hours, a calculation that would have taken at least 80 days using a conventional multislice approach.
 [15] arXiv:1908.07629 [pdf, other]

Title: Spinpolarized currents in corrugated graphene nanoribbonsComments: 9 pages, 9 figuresSubjects: Mesoscale and Nanoscale Physics (condmat.meshall)
We investigate the production of spinpolarized currents in corrugated graphene nanoribbons. We model the corrugation as multiple regions with Rashba spinorbit interactions. Concave and convex curvatures are modeled as Rashba regions with opposite signs. Numerical examples for different separated Rashbazone geometries calculated within the tightbinding approximation are provided. Remarkably, the spinpolarized current in a system with several Rashba areas can be enhanced with respect to the case with a single Rashba part of the same total area. The enhancement is larger for configurations with multiple regions with the same Rashba sign. Additionally, we relate the appearance of the spinpolarized currents to novel symmetry relations between the spindependent conductances. These symmetries turn out to be a combination of different symmetry operations in real and spin spaces, as those occurring in nonplanar systems like carbon nanotubes. Our results show that twodimensional devices with Rashba spinorbit interaction can be used as excellent spintronic devices in an allelectrical or mechanical setup.
 [16] arXiv:1908.07648 [pdf]

Title: Hot exciton transport in WSe2 monolayersSubjects: Mesoscale and Nanoscale Physics (condmat.meshall); Applied Physics (physics.appph); Optics (physics.optics)
We experimentally demonstrate hot exciton transport in hBN encapsulated WSe2 monolayers via spatially and temporally resolved photoluminescence measurements at room temperature. We show that the nonlinear evolution of the mean squared displacement of the nonresonantly excited hot exciton gas is primarily due to the relaxation of its excess kinetic energy and is characterized by a densitydependent fast expansion that converges to a slower, constant rate expansion. We also observe saturation of the hot exciton gas' expansion rate at high excitation densities due to the balance between Augerassisted hot exciton generation and the phononassisted hot exciton relaxation processes.
 [17] arXiv:1908.07649 [pdf, other]

Title: Nematic state in CeAuSb$_{2}$Authors: S. Seo, Xiaoyu Wang, S. M. Thomas, M. C. Rahn, D. Carmo, F. Ronning, E. D. Bauer, R. D. dos Reis, M. Janoschek, J. D. Thompson, R. M. Fernandes, P. F. S. RosaSubjects: Strongly Correlated Electrons (condmat.strel)
At ambient pressure and zero field, tetragonal CeAuSb$_{2}$ hosts stripe antiferromagnetic order at $T_{N} = 6.3$ K. Here we first show via bulk thermodynamic probes and xray diffraction measurements that this magnetic order is connected with a structural phase transition to a superstructure which likely breaks $C_{4}$ symmetry, thus signaling nematic order. The temperaturefieldpressure phase diagram of CeAuSb$_{2}$ subsequently reveals the emergence of additional ordered states under applied pressure at a multicritical point. Our phenomenological model supports the presence of a vestigial nematic phase in CeAuSb$_{2}$ akin to ironbased hightemperature superconductors; however, superconductivity, if present, remains to be discovered.
 [18] arXiv:1908.07652 [pdf, ps, other]

Title: Novel universality class for the ferromagnetic transition in the low carrier concentration systems UTeS and USeS exhibiting large negative magnetoresistanceComments: 8 pages, 6 figuresJournalref: Phys. Rev. B 100, 064413 (2019)Subjects: Strongly Correlated Electrons (condmat.strel)
We report the novel critical behavior of magnetization in low carrier concentration systems UTeS and USeS that exhibit the large negative magnetoresistance around the ferromagnetic transition temperatures T_C ~ 85 and 23 K, respectively. UTeS and USeS crystallize in the same orthorhombic TiNiSitype crystal structure as those of uranium ferromagnetic superconductors URhGe and UCoGe. We determine the critical exponents, beta for the spontaneous magnetization M_s, gamma for the magnetic susceptibility chi, and delta for the magnetization isotherm at T_C with several methods. The ferromagnetic states in UTeS and USeS have strong uniaxial magnetic anisotropy. However, the critical exponents in the two compounds are different from those in the threedimensional Ising model with shortrange magnetic exchange interactions. Similar sets of the critical exponents have been reported for the uranium ferromagnetic superconductors UGe_2 and URhGe, and uranium intermetallic ferromagnets URhSi, UIr and U(Co_0.98Os_0.02)Al. The universality class of the ferromagnetic transitions in UTeS and USeS may belong to the same one for the uranium compounds. The novel critical phenomenon associated with the ferromagnetic transition is observed not only in the uranium intermetallic ferromagnets with the itinerant 5f electrons but also in the low carrier concentration systems UTeS and USeS with the localized 5f electrons. The large negative magnetoresistance in UTeS and USeS, and the superconductivity in UGe_2 and URhGe share the similarity of their closeness to the ferromagnetism characterized by the novel critical exponents.
 [19] arXiv:1908.07671 [pdf, other]

Title: Magneticfield Induced Quantum Phases in Tensor Network Study of Kitaev MagnetsAuthors: HyunYong Lee, Ryui Kaneko, Li Ern Chern, Tsuyoshi Okubo, Youhei Yamaji, Naoki Kawashima, Yong Baek KimSubjects: Strongly Correlated Electrons (condmat.strel)
Recent discovery of the halfquantized thermal Hall conductivity in $\alpha$RuCl$_3$, a candidate material for the Kitaev spin liquid, suggests the presence of a highlyentangled quantum state in external magnetic fields. This fieldinduced phase appears between the lowfield zigzag magnetic order and the highfield polarized state. Motivated by this experiment, we study possible fieldinduced quantum phases in theoretical models of the Kitaev magnets, using the twodimensional tensor network approach or infinite tensor product states (iTPS). More specifically, we map out the magneticfield phase diagram of the $K$$\Gamma$$\Gamma'$ model, where $K$ is the ferromagnetic Kitaev interaction and $\Gamma$, $\Gamma'$ are additional bonddependent anisotropic interactions between spin1/2 moments. We find various novel quantum ground states in addition to the chiral Kitaev spin liquid occupying a small area in the phase diagram. They form a band of emergent quantum phases in an intermediate window of external magnetic fields, somewhat reminiscent of the experiment. We discuss the implications of these results in view of the experiment and previous theoretical studies.
 [20] arXiv:1908.07692 [pdf, ps, other]

Title: Majorana zero modes by engineering topological kink states in two dimensional electron gasComments: 6 page, 4 figures, Supplementary includeSubjects: Mesoscale and Nanoscale Physics (condmat.meshall)
Majorana zero modes (MZMs)bearing potential applications for topological quantum computingare verified in quasionedimensional (1D) Fermion systems, including semiconductor nanowires, magnetic atomic chains, planar Josephson junctions. However, the existence of multibands in these systems makes the MZMs fragile to the influence of disorder. Moreover, in practical perspective, the proximity induced superconductivity may be difficult and restricted for 1D systems. Here, we propose a flexible route to realize MZMs through 1D topological kink states by engineering a 2D electron gas with antidot lattices, in which both the aforementioned issues can be avoided owing to the robustness of kink states and the intrinsically attainable superconductivity in highdimensional systems. The MZMs are verified to be quite robust against disorders and the bending of kink states, and can be conveniently tuned by varying the Rashba spinorbit coupling strength. Our proposal provides an experimental feasible platform for MZMs with systematic manipulability and assembleability based on the present techniques in 2D electron gas system.
 [21] arXiv:1908.07702 [pdf, other]

Title: Effects of staggered DzyaloshinskiiMoriya interactions in a quasitwodimensional ShastrySutherland modelComments: 7 pages, 6 figuresSubjects: Quantum Gases (condmat.quantgas); Strongly Correlated Electrons (condmat.strel)
Frustrated quantum spin systems exhibit exotic physics induced by external magnetic field with anisotropic interactions. Here, we study the effect of nonuniform DzyaloshinskiiMoriya (DM) interactions on a quasi$2$D ShastrySutherland lattice using a matrix product states (MPS) algorithm. We first recover the magnetization plateau structure present in this geometry and then we show that both interdimer and intradimer DM interactions significantly modify the plateaux. The nonnumberconserving intradimer interaction smoothen the shape of the magnetization curve, while the numberconserving interdimer interaction induces different small plateaux which are signatures of the finite size of the system. Interestingly, the interdimer DM interaction induces chirality in the system. We thus characterize these chiral phases with particular emphasis to their robustness against intradimer DM interactions.
 [22] arXiv:1908.07710 [pdf]

Title: Twodimensional Ferromagnetic van der Waals CrX3 (X=Cl, Br, I) Monolayers with Enhanced Anisotropy and Curie TemperatureComments: 4 figures and 11 pagesSubjects: Materials Science (condmat.mtrlsci)
Among the recently widely studied van der Waals layered magnets CrX3 (X=Cl, Br, I), CrCl3 monolayer (ML) is particularly puzzling as it is solely shown by experiments to have an inplane magnetic easy axis and, furthermore, all of previous firstprinciples calculation results contradict this. Through systematical firstprinciples calculations,we unveil that its inplane shape anisotropy that dominates over its weak perpendicular magnetocrystalline anisotropy is responsible for the inplane magnetic easy axis of CrCl3 ML. To tune the inplane ferromagnetism of CrCl3 ML into the desirable perpendicular one, we propose substituting Cr with isovalent tungsten (W). We find that CrWCl6 has a strong perpendicular magnetic anisotropy and a high Curie temperature up to 76 K. Our work not only gives insight into understanding the twodimensional ferromagnetism of van der Waals MLs but also sheds new light on engineering their performances for nanodevices.
 [23] arXiv:1908.07714 [pdf, other]

Title: Effective transport properties of conformal Voronoibounded columns via recurrent boundary element expansionsAuthors: Matthew D. ArnoldSubjects: Disordered Systems and Neural Networks (condmat.disnn); Computational Physics (physics.compph)
Effective transport properties of heterogeneous structures are predicted by geometric microstructural parameters, but these can be difficult to calculate. Here, a boundary element code with a recurrent series method accurately and efficiently determines the high order parameters of polygonal and conformal prisms in regular twodimensional lattices and Voronoi tessellations (VT). This reveals that proximity to simpler estimates is associated with: centroidal VT (cf random VT), compactness, and VT structures (cf similarly compact semiregular lattices). An error in previously reported values for triangular lattices is noted.
 [24] arXiv:1908.07728 [pdf, other]

Title: Ordering phenomena of spin trimers accompanied by large geometrical Hall effectAuthors: Shang Gao, Max Hirschberger, Oksana Zaharko, Taro Nakajima, Takashi Kurumaji, Akiko Kikkawa, Junichi Shiogai, Atsushi Tsukazaki, Shojiro Kimura, Satoshi Awaji, Yasujiro Taguchi, Takahisa Arima, Yoshinori TokuraComments: 15 pages, 12 figuresSubjects: Strongly Correlated Electrons (condmat.strel); Materials Science (condmat.mtrlsci)
The wavefuntion of conduction electrons moving in the background of a noncoplanar spin structure can gain a quantal phase  Berry phase  as if the electrons were moving in a strong fictitious magnetic field. Such an emergent magnetic field effect is approximately proportional to the solid angle subtended by the spin moments on three neighbouring spin sites, termed the scalar spin chirality. The entire spin chirality of the crystal, unless macroscopically canceled, causes the geometrical Hall effect of realspace Berryphase origin, whereas the intrinsic anomalous Hall effect (AHE) in a conventional metallic ferromagnet is of the momentumspace Berryphase origin induced by relativistic spinorbit coupling (SOC). Here, we report the ordering phenomena of the spintrimer scalar spin chirality and the consequent large geometrical Hall effect in the breathing kagom\'e lattice compound Dy$_3$Ru$_4$Al$_{12}$, where the Dy$^{3+}$ moments form noncoplanar spin trimers with local spin chirality. Using neutron diffraction, we show that the local spin chirality of the spin trimers as well as its ferroic/antiferroic orders can be switched by an external magnetic field, accompanying large changes in the geometrical Hall effect. Our finding reveals that systems composed of tunable spin trimers can be a fertile field to explore large emergent electromagnetic responses arising from realspace topological magnetic orders.
 [25] arXiv:1908.07730 [pdf]

Title: Pure spin current in a robust pigmentred filmComments: 15 pages, 4 figuresSubjects: Materials Science (condmat.mtrlsci)
We report the spin current properties in a pigmentred (perylene3,4,9,10tetracarboxylic dianhydride: PTCDA) film prepared by thermal evaporation. In a palladium(Pd)/PTCDA/Ni80Fe20 trilayer sample, a pure spincurrent is generated in the PTCDA layer by the spinpumping of the Ni80Fe20. The spin current is absorbed into the Pd layer, converted into a charge current with the inverse spinHall effect in Pd, and detected as an electromotive force. This is clear evidence for the pure spin current in a PTCDA film, and it is confirmed that a PTCDA film is useful not only as a robust protection layer material but also as a spintronic material.
 [26] arXiv:1908.07735 [pdf, other]

Title: Negative excitonic diffusion in transition metal dichalcogenidesComments: 6 pages, 5 figuresSubjects: Mesoscale and Nanoscale Physics (condmat.meshall)
While exciton relaxation in transition metal dichalcogenides (TMDs) has been intensively studied, spatial exciton propagation has received only little attention  in spite of being a key process for optoelectronics and having already shown interesting unconventional behaviours (e.g. spatial halos). Here, we study the spatiotemporal dynamics in TMDs and track the way of optically excited excitons in time, momentum, and space. In particular, we investigate the temperaturedependent exciton diffusion including the remarkable exciton landscape constituted by bright and dark states. Based on a fully quantum mechanical approach, we show at low temperatures an unexpected negative transient diffusion. This phenomenon can be traced back to the existence of dark exciton states in TMDs and is a result of an interplay between spatial exciton diffusion and intervalley excitonphonon scattering.
 [27] arXiv:1908.07739 [pdf, other]

Title: One and threedimensional quantum phase transitions and anisotropy in Rb$_{2}$Cu$_{2}$Mo$_{3}$O$_{12}$Authors: S. Hayashida, D. Blosser, K. Yu. Povarov, Z. Yan, S. Gvasaliya, A. N. Ponomaryov, S. A. Zvyagin, A. ZheludevSubjects: Strongly Correlated Electrons (condmat.strel)
Single crystal samples of the frustrated quasi onedimensional quantum magnet Rb$_{2}$Cu$_{2}$Mo$_{3}$O$_{12}$ are investigated by magnetic, thermodynamic and electron spin resonance (ESR) measurements. Quantum phase transitions between the gapped, magnetically ordered and fully saturated phases are observed. Surprisingly, the former has a distinctive threedimensional character, while the latter is dominated by onedimensional quantum spin fluctuations. The entire $H$$T$ phase diagram is mapped out and found to be substantially anisotropic. In particular, the lower critical fields differ by over 50\% depending on the direction of applied field, while the upper ones are almost isotropic, as is the magnetization above saturation. The ESR spectra are strongly dependent on field orientation and point to a helical structure with a rigidly defined spin rotation plane.
 [28] arXiv:1908.07764 [pdf, other]

Title: Diffusioninfluenced reaction rates in the presence of pair interactionsSubjects: Soft Condensed Matter (condmat.soft)
The kinetics of bimolecular reactions in solution depends, among other factors, on intermolecular forces such as steric repulsion or electrostatic interaction. Microscopically, a pair of molecules first has to meet by diffusion before the reaction can take place. In this work, we establish an extension of Doi's volume reaction model to molecules interacting via pair potentials, which is a key ingredient for interactingparticlebased reactiondiffusion (iPRD) simulations. As a central result, we relate model parameters and macroscopic reaction rate constants in this situation. We solve the corresponding reactiondiffusion equation in the steady state and derive semianalytical expressions for the reaction rate constant and the local concentration profiles. Our results apply to the full spectrum from wellmixed to diffusionlimited kinetics. For limiting cases, we give explicit formulas, and we provide a computationally inexpensive numerical scheme for the general case, including the intermediate, diffusioninfluenced regime. The obtained rate constants decompose uniquely into encounter and formation rates, and we discuss the effect of the potential on both subprocesses, exemplified for a soft harmonic repulsion and a LennardJones potential. The analysis is complemented by extensive stochastic iPRD simulations, and we find excellent agreement with the theoretical predictions.
 [29] arXiv:1908.07768 [pdf, other]

Title: Nonaffinity and fluidcoupled viscoelastic plateau for immersed fiber networksComments: 5 pages, 5 figures. Supplementary information provided in submission ("suppInf.pdf")Subjects: Soft Condensed Matter (condmat.soft); Biological Physics (physics.bioph)
We employ a matrixbased solver for the linear rheology of fluidimmersed disordered spring networks to reveal four distinct dynamic response regimes. One regime  completely absent in the known vacuum response  exhibits coupled fluid flow and network deformation, with both components responding nonaffinely. This regime contains an additional plateau (peak) in the frequencydependent storage (loss) modulus  features which vanish without full hydrodynamic interactions. The mechanical response of immersed networks such as biopolymers and hydrogels is thus richer than previously established, and offers additional modalities for design and control through fluid interactions.
 [30] arXiv:1908.07770 [pdf, other]

Title: Ensemble inequivalence in the BlumeEmeryGriffiths model near a fourth order critical pointComments: 9 pages, 10 figuresSubjects: Statistical Mechanics (condmat.statmech)
The canonical phase diagram of the BlumeEmeryGriffiths (BEG) model with infiniterange interactions is known to exhibit a fourth order critical point at some negative value of the biquadratic interaction $K<0$. Here we study the microcanonical phase diagram of this model for $K<0$, extending previous studies which were restricted to positive $K$. A fourth order critical point is found to exist at coupling parameters which are different from those of the canonical ensemble. The microcanonical phase diagram of the model close to the fourth order critical point is studied in detail revealing some distinct features from the canonical counterpart.
 [31] arXiv:1908.07771 [pdf, other]

Title: Collective oscillations of a twocomponent Fermi gas on the repulsive branchComments: 8 pages, 8 figuresSubjects: Quantum Gases (condmat.quantgas)
We calculate frequencies of collective oscillations of twocomponent Fermi gas that is kept on the repulsive branch of its energy spectrum. Not only is a paramagnetic phase explored, but also a ferromagnetically separated one. Both in, and outofphase perturbations are investigated, showing contributions from various gas excitations. Additionally, we compare results coming from both timedependent HartreeFock and densityfunctional approaches.
 [32] arXiv:1908.07804 [pdf, other]

Title: Halfmetallic ferromagnetism and Ruinduced localization in quaternary Heusler alloy CoRuMnSiComments: 9 pages, 8 figuresSubjects: Materials Science (condmat.mtrlsci)
We report a combined theoretical and experimental investigation of halfmetallic ferromagnetism in equiatomic quaternary Heusler alloy CoRuMnSi. Room temperature XRD analysis reveals that the alloy crystallizes in L21 disorder instead of pristine Ytype structure due to 50% swap disorder between the tetrahedral sites, i.e., Co and Ru atoms. Magnetization measurements reveal a net magnetization of 4 $\mu_B$ with Curie temperature of ~780 K. Resistivity measurement reveals the presence of localization effect below 35 K while above 100 K, a linear dependence is observed. Resistivity behavior indicates the absence of single magnon scattering, which indirectly supports the halfmetallic nature. The majority spin band near the Fermi level clearly indicates the overlap of flat eg bands with sharply varying conduction bands that are responsible for the localization. Indepth analysis of the projected atomic dorbital character of band structure reveals unusual bonding, giving rise to the flat eg bands purely arising out of Ru ions. CoRu swap disorder calculations indicate the robustness of halfmetallic nature, even when the structure changes from Ytype to L21type, with no major change in the net magnetization of the system. Thus, robust halfmetallic nature, stable structure, and high Curie temperature make this alloy quite a promising candidate to be used as a source of highly spinpolarized currents in spintronic applications.
 [33] arXiv:1908.07843 [pdf]

Title: Microstructure and Elastic Constants of Transition Metal Dichalcogenide Monolayers from Friction and Shear Force MicroscopyAuthors: Xiaomin Xu, Thorsten Schultz, Ziyu Qin, Nikolai Severin, Benedikt Haas, Sumin Shen, Jan N. Kirchhof, Andreas Opitz, Christoph T. Koch, Kirill Bolotin, Jürgen P. Rabe, Goki Eda, Norbert KochJournalref: Advanced Materials 30 1803748 (2018)Subjects: Materials Science (condmat.mtrlsci)
Optical and electrical properties of twodimensional transition metal dichalcogenides (TMDCs) grown by chemical vapor deposition (CVD) are strongly determined by their microstructure. Consequently, the visualization of spatial structural variations is of paramount importance for future applications. Here we demonstrate how grain boundaries, crystal orientation, and strain fields can unambiguously be identified with combined lateral force microscopy (LFM) and transverse shear microscopy (TSM) for CVDgrown tungsten disulfide (WS2) monolayers, on length scales that are relevant for optoelectronic applications. Further, angledependent TSM measurements enable us to acquire the fourthorder elastic constants of monolayer WS2 experimentally. Our results facilitate highthroughput and nondestructive microstructure visualization of monolayer TMDCs, insights into their elastic properties, thus providing an accessible tool to support the development of advanced optoelectronic devices based on such twodimensional semiconductors.
 [34] arXiv:1908.07848 [pdf, other]

Title: Phaseseparated symmetrybreaking vortexlattice in a binary BoseEinstein condensateAuthors: S. K. AdhikariComments: arXiv admin note: text overlap with arXiv:1811.06816Subjects: Quantum Gases (condmat.quantgas); Pattern Formation and Solitons (nlin.PS)
We study spontaneoussymmetrybreaking circularlyasymmetric phase separation of vortex lattices in a rapidly rotating harmonicallytrapped quasitwodimensional (quasi2D) binary BoseEinstein condensate (BEC) with repulsive inter and intraspecies interactions. The phase separated vortex lattices of the components appear in different regions of space with no overlap between the vortices of the two components, which will permit an efficient experimental observation of such vortices and accurate study of the effect of atomic interaction on such vortex lattice. Such phase separation takes place when the intraspecies interaction energies of the two components are equal or nearly equal with relatively strong interspecies repulsion. When the intraspecies energies are equal, the two phaseseparated vortex lattices have identical semicircular shapes with one being the parity conjugate of the other. When the intraspecies energies are nearly equal, the phase separation is also complete but the vortex lattices have different shapes. We demonstrate our claim with a numerical solution of the meanfield GrossPitaevskii equation for a rapidly rotating quasi2D binary BEC.
 [35] arXiv:1908.07853 [pdf, other]

Title: Multimode probing of superfluid $\mathbf{^4He}$ by tuning forksAuthors: A. Guthrie, R.P. Haley, A. Jennings, S. Kafanov, O. Kolosov, M. Mucientes, M.T. Noble, Yu. A. Pashkin, G.R. Pickett, V. Tsepelin, D.E. Zmeev, V. EfimovComments: 4 pages, 3 figuresSubjects: Other Condensed Matter (condmat.other); Quantum Gases (condmat.quantgas)
Flexural mode vibrations of miniature piezoelectric tuning forks (TF) are known to be highly sensitive to superfluid excitations and quantum turbulence in $\mathrm{^3He}$ and $\mathrm{^4He}$ quantum fluids, as well as to the elastic properties of solid $\mathrm{^4He}$, complementing studies by large scale torsional resonators. Here we explore the sensitivity of a TF, capable of simultaneously operating in both the flexural and torsional modes, to excitations in the normal and superfluid $\mathrm{^4He}$. The torsional mode is predominantly sensitive to shear forces at the sensor  fluid interface and much less sensitive to changes in the density of the surrounding fluid when compared to the flexural mode. Although we did not reach the critical velocity for quantum turbulence onset in the torsional mode, due to its order of magnitude higher frequency and increased acoustic damping, the torsional mode was directly sensitive to fluid excitations, linked to quantum turbulence created by the flexural mode. The combination of two dissimilar modes in a single TF sensor can provide a means to study the details of elementary excitations in quantum liquids, and at interfaces between solids and quantum fluid.
 [36] arXiv:1908.07868 [pdf, other]

Title: Tunable roomtemperature spin galvanic and spin Hall effects in van der Waals heterostructuresAuthors: L. Antonio Benitez, Williams Savero Torres, Juan F. Sierra, Matias Timmermans, Jose H. Garcia, Stephan Roche, Marius V. Costache, Sergio O. ValenzuelaComments: 13 pages, 4 figuresSubjects: Mesoscale and Nanoscale Physics (condmat.meshall); Applied Physics (physics.appph)
Spinorbit coupling stands as a powerful tool to interconvert charge and spin currents and to manipulate the magnetization of magnetic materials through the spin torque phenomena. However, despite the diversity of existing bulk materials and the recent advent of interfacial and lowdimensional effects, control of the interconvertion at roomtemperature remains elusive. Here, we unequivocally demonstrate strongly enhanced roomtemperature spintocharge (StC) conversion in graphene driven by the proximity of a semiconducting transition metal dichalcogenide(WS2). By performing spin precession experiments in properly designed Hall bars, we separate the contributions of the spin Hall and the spin galvanic effects. Remarkably, their corresponding conversion effiencies can be tailored by electrostatic gating in magnitude and sign, peaking nearby the charge neutrality point with a magnitude that is comparable to the largest efficiencies reported to date. Such an unprecedented electricfield tunability provides a new building block for spin generation free from magnetic materials and for ultracompact magnetic memory technologies.
 [37] arXiv:1908.07881 [pdf, other]

Title: Apollonian Packing in Polydisperse EmulsionsComments: 5 pages, 4 figuresSubjects: Soft Condensed Matter (condmat.soft); Materials Science (condmat.mtrlsci); Chemical Physics (physics.chemph)
We have discovered the existence of polydisperse High InternalPhaseRatio Emulsions (HIPE) in which the internalphase droplets, present at 95% volume fraction, remain spherical and organize themselves in the available space according to Apollonian packing rules. These polydisperse HIPE are formed during emulsification of surfactantpoor compositions of oilsurfactantwater twophase systems. Their droplet sizedistributions evolve spontaneously towards power laws with the Apollonian exponent. SmallAngle XRay Scattering performed on aged HIPEs demonstrated that the droplet packing structure coincided with that of a numerically simulated Random Apollonian Packing. We argue that these peculiar, spacefilling assemblies are a result of coalescence and fragmentation processes obeying simple geometrical rules of conserving total volume and total interface area.
 [38] arXiv:1908.07900 [pdf]

Title: Fatigueresistant highperformance elastocaloric materials via additive manufacturingAuthors: Huilong Hou, Emrah Simsek, Tao Ma, Nathan S. Johnson, Suxin Qian, Cheikh Cisse, Drew Stasak, Naila Al Hasan, Lin Zhou, Yunho Hwang, Reinhard Radermacher, Valery I. Levitas, Matthew J. Kramer, Mohsen Asle Zaeem, Aaron P. Stebner, Ryan T. Ott, Jun Cui, Ichiro TakeuchiComments: 38 pages, 3 figures, 8 supplementary figures, 1 supplementary tableSubjects: Materials Science (condmat.mtrlsci)
Elastocaloric cooling, which exploits the latent heat released and absorbed as stressinduced phase transformations are reversibly cycled in shape memory alloys, has recently emerged as a frontrunner in nonvaporcompression cooling technologies. The intrinsically high thermodynamic efficiency of elastocaloric materials is limited only by work hysteresis. Here, we report on creating highperformance lowhysteresis elastocaloric cooling materials via additive manufacturing of TitaniumNickel (TiNi) alloys. Contrary to established knowledge of the physical metallurgy of TiNi alloys, intermetallic phases are found to be beneficial to elastocaloric performances when they are combined with the binary TiNi compound in nanocomposite configurations. The resulting microstructure gives rise to quasilinear stressstrain behaviors with extremely small hysteresis, leading to enhancement in the materials efficiency by a factor of five. Furthermore, despite being composed of more than 50% intermetallic phases, the reversible, repeatable elastocaloric performance of this material is shown to be stable over one million cycles. This result opens the door for direct implementation of additive manufacturing to elastocaloric cooling systems where versatile design strategy enables both topology optimization of heat exchangers as well as unique microstructural control of metallic refrigerants.
 [39] arXiv:1908.07907 [pdf, other]

Title: Nonreciprocity and Unidirectional Invisibility in Cavity MagnonicsComments: 6 pages, 4 figuresSubjects: Mesoscale and Nanoscale Physics (condmat.meshall); Quantum Physics (quantph)
We reveal the cooperative effect of coherent and dissipative magnonphoton couplings in an open cavity magnonic system, which leads to nonreciprocity with a considerably large isolation ratio and flexible controllability. Furthermore, we discover unidirectional invisibility for microwave propagation, which appears at the zerodamping condition for hybrid magnonphoton modes. A simple model is developed to capture the generic physics of the interference between coherent and dissipative couplings, which accurately reproduces the observations over a broad range of parameters. This general scheme could inspire methods to achieve nonreciprocity in other systems.
 [40] arXiv:1908.07923 [pdf, ps, other]

Title: Suppression of ferromagnetic spin fluctuations in the filled skutterudite superconductor SrOs4As12 revealed by 75As NMRNQR measurementsComments: 8 pages, 5 figures, accepted for publication in Phys. Rev. B. arXiv admin note: substantial text overlap with arXiv:1810.08302Subjects: Strongly Correlated Electrons (condmat.strel); Superconductivity (condmat.suprcon)
Motivated by the recent observation of ferromagnetic spin correlations in the filled skutterudite SrFe$_4$As$_{12}$ [Ding et al., Phys. Rev. B 98, 155149 (2018)], we have carried out $^{75}$As nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR) measurements to investigate the role of magnetic fluctuations in a newly discovered isostructural superconductor SrOs$_4$As$_{12}$ with a superconducting transition temperature of $T_{\rm c}$ $\sim$ 4.8 K. Knight shift $K$ determined by the NQR spectrum under a small magnetic field ($\le$ 0.5 T) is nearly independent of temperature, consistent with the temperature dependence of the magnetic susceptibility. The nuclear spinlattice relaxation rate divided by temperature, 1/$T_1T$, is nearly independent of temperature above $\sim$ 50 K and increases slightly with decreasing temperature below the temperature. The temperature dependence is reasonably explained by a simple model where a flat band structure with a small ledge near the Fermi energy is assumed. By comparing the present NMR data with those in SrFe$_4$As$_{12}$, we found that the values of $K$ and $1/T_1T$ in SrOs$_4$As$_{12}$ are smaller than those in SrFe$_4$As$_{12}$, indicating no obvious ferromagnetic spin correlations in SrOs$_4$As$_{12}$. From the temperature dependence of 1/$T_1$ in the superconducting state, an $s$wave superconductivity is realized.
 [41] arXiv:1908.07939 [pdf, ps, other]

Title: Steady state cyclic behaviour of a halfplane contact in partial slip subject to varying normal load, moment, shear load, and moderate differential bulk tensionComments: 13 pages, 6 figuesSubjects: Soft Condensed Matter (condmat.soft)
A new solution for a general halfplane contact in the steady state is presented. The contacting bodies are subject to a set of constant loads  normal force, shear force and bulk tension parallel with the interface  together with an oscillatory set of the same quantities. Partial slip conditions are expected to ensue for a range of these quantities. In addition, the line of action of the normal load component does not necessarily need to pass the centreline of the contact, thereby introducing a moment and asymmetry in the contact extent. This advancement enables a mapping to be formalised between the normal and tangential problem. An exact and easy to apply recipe is defined.
 [42] arXiv:1908.07945 [pdf, ps, other]

Title: Inertial migration of neutrallybuoyant particles in superhydrophobic channelsComments: 10 pages, 10 figuresSubjects: Soft Condensed Matter (condmat.soft); Fluid Dynamics (physics.fludyn)
At finite Reynolds numbers particles migrate across flow streamlines to their equilibrium positions in microchannels. Such a migration is attributed to an inertial lift force, and it is wellknown that the equilibrium location of neutrallybuoyant particles is determined only by their size and the channel Reynolds number. Here we demonstrate that the decoration of a bottom wall of the channel by superhydrophobic grooves provides additional possibilities for manipulation of neutrallybuoyant particles. It is shown that the effective anisotropic hydrodynamic slip of such a bottom wall can be readily used to alter the equilibrium positions of particles and to generate their motion transverse to the pressure gradient. These results may guide the design of novel inertial microfluidic devices for efficient sorting of neutrallybuoyant microparticles by their size.
 [43] arXiv:1908.07950 [pdf, other]

Title: On the multifractal dimensions and statistical properties of critical ensembles characterized by the three classical WignerDyson symmetry classesComments: 9 pages, 4 figuresSubjects: Disordered Systems and Neural Networks (condmat.disnn); Mathematical Physics (mathph)
We introduce a powerlaw banded random matrix model for the third of the three classical WignerDyson ensembles, i.e., the symplectic ensemble. A detailed analysis of the statistical properties of its eigenvectors and eigenvalues, at criticality, is presented. This ensemble is relevant for timereversal symmetric systems with strong spinorbit interaction. For the sake of completeness, we also review the statistical properties of eigenvectors and eigenvalues of the powerlaw random banded matrix model for the corresponding systems in the presence and absence of time reversal invariance, previously considered in the literature. Our results show a good agreement with heuristic relations for the eigenstate and eigenenergy statistics at criticality, proposed in previous studies. With this, we provide a full picture of the powerlaw random banded matrix model corresponding to the three classical WignerDyson ensembles.
 [44] arXiv:1908.07953 [pdf, other]

Title: Quasiclassical circuittheory of contiguous disordered multiband superconductorsComments: 14 pages, 8 figuresSubjects: Strongly Correlated Electrons (condmat.strel)
We consider a general problem of a Josephson contact between two multiband superconductors with coexisting superconducting and magnetic phases. As a particular example, we use the quasiclassical theory of superconductivity to study the properties of a Josephson contact between two disordered $s^{\pm}$wave superconductors allowing for the coexistence between superconductivity and spindensitywave orders. The intra and interband scattering effects of disorder are treated within the selfconsistent Born approximation. We calculate the spatial profile of the corresponding order parameters on both sides of the interface assuming that the interface has finite reflection coefficient and use our results to evaluate the local density of states at the interface as well as critical supercurrent through the junction as a function of phase or applied voltage. Our methods are particularly well suited for describing spatially inhomogeneous states of ironbased superconductors where controlled structural disorder can be created by an electron irradiation. We reveal the connection between our theory and the circuittheory of Andreev reflection and extend it to superconducting junctions of arbitrary nature. Lastly, we outline directions for further developments in the context of proximity circuits of correlated electron systems.
 [45] arXiv:1908.07969 [pdf, other]

Title: Magnetic signatures of domain walls in $s+is$ and $s+id$ superconductors: observability and what that can tell us about the superconducting order parameterComments: 8 pages, 5 figuresSubjects: Superconductivity (condmat.suprcon)
One of the defining features of spontaneously broken time reversal symmetry (BTRS) is the existence of domain walls, the detection of which would be strong evidence for such systems. There is keen interest in BTRS currently, in part due to recent muon spin rotation experiments, which have pointed towards $\textrm{Ba}_{1x}\textrm{K}_x\textrm{Fe}_2\textrm{As}_2$ exhibiting spontaneously broken time reversal symmetry. A key question however is how to differentiate between the different theoretical models which describe such a state. Two particularly popular choices of model are $s+is$ and $s+id$ superconducting states. In this paper we obtain solutions for domain walls in $s+is$ and $s+id$ systems, including the effects of anisotropies, showing that in general they exhibit strong spontaneous magnetic fields that extend along the entire length of the domain wall. We will demonstrate the qualitative difference between the magnetic signatures of $s+is$ and $s+id$ domain walls and propose a procedure, that one could use to extract the superconducting pairing symmetry from the magnetic field response of domain walls.
 [46] arXiv:1908.07982 [pdf, other]

Title: Nonaffine lattice dynamics with the Ewald method reveals strongly nonaffine elasticity of αquartzSubjects: Materials Science (condmat.mtrlsci)
A lattice dynamical formalism based on nonaffine response theory is derived for noncentrosymmetric crystals, accounting for longrange interatomic interactions using the Ewald method. The framework takes equilibrated static configurations as input to compute the elastic constants in excellent agreement with both experimental data and calculations under strain. Besides this methodological improvement, which enables faster evaluation of elastic constants without the need of explicitly simulating the deformation process, the framework provides insights into the nonaffine contribution to the elastic constants of {\alpha}quartz. It turns out that, due to the noncentrosymmetric lattice structure, the nonaffine (softening) correction to the elastic constants is very large, such that the overall elastic constants are at least 34 times smaller than the affine BornHuang estimat
 [47] arXiv:1908.07995 [pdf]

Title: On the Magnetism of C14 Nb(Fe89.4Al10.6)2 Laves Phase Intermetallic CompoundComments: 12 Pages, 4 Figures, 18 ReferencesSubjects: Materials Science (condmat.mtrlsci); Strongly Correlated Electrons (condmat.strel)
C14 Nb(Fe89.4Al10.6)2 Laves phase intermetallic compound was investigated by DC magnetization (M) measurements performed in the temperature (T) interval of 20 to 175 K,under an applied magnetic field (H) ranging between 50 and 1250 Oe. Magnetization curves were recorded in the fieldcooled (FC) and in the zerofieldcooled (ZFC) modes. They clearly showed an irreversible character that vanished at H=1250 Oe. Both magnetization curves exhibited welldefined peaks around T_N =72.3 K whose positions were Hindependent, so they were identified as the compound's N\'eel temperature. The existence of irreversibility which decreases with H testify to a reentrant character of magnetism in the studied compound. An increase of both MFC and MZFC observed below TN likely indicates a mixed i.e. ferromagnetic and antiferromagnetic ground magnetic state of the studied system.
 [48] arXiv:1908.08002 [pdf, other]

Title: Virtual clusters model on branching random graphs for confined fluid thermodynamics in heterogeneous solid geometryComments: 24 pages, 7 figuresSubjects: Disordered Systems and Neural Networks (condmat.disnn); Mesoscale and Nanoscale Physics (condmat.meshall); Statistical Mechanics (condmat.statmech); Mathematical Physics (mathph)
Fluid properties near rough surfaces are crucial in both a description of fundamental surface phenomena and modern industrial material design implementations. One of the most powerful approach to model real rough materials is based on the surface representation in terms of random geometry. Understanding the influence of random solid geometry on the low temperature fluid thermodynamics is a cutting edge problem. Therefor this work extends recent studies bypassing high temperature expansion and small heterogeneity scale. We introduce random branching trees whose topology reflects the hierarchical properties of random solid geometry. This mathematical representation allows to obtain averaged free energy using novel statistical model of virtual clusters interacting through random ultrametric pairwise potentials. Excellent agreement with direct Monte Carlo calculations is obtained. Moreover, we find that this model leads to interesting features of fluidsolid interactions that have not been discussed in the literature. Our results demonstrate that at low temperature a significant impact to fluidsolid interface energy is induced by hierarchical structure of random geometry. Due to the interdisciplinary nature of the study, our approach can be generalized and applied to a wide range of quenched disorder systems on random graphs. Cooperative phenomena in biological populations and social networks seem most attractive.
 [49] arXiv:1908.08008 [pdf, other]

Title: Small polarons and the Janus nature of $\text{TiO}_\text{2}(110)$Subjects: Materials Science (condmat.mtrlsci); Computational Physics (physics.compph)
Polarons are ubiquitous in many semiconductors and have been linked with conductivity and optical response of materials for photovoltaics and heterogeneous catalysis, yet how surface polarons influence adsorption remains unclear. Here, by modelling the surface of rutile titania using density functional theory, we reveal the effect of small surface polarons on water adsorption, dissociation, and hydrogen bonding. On the one hand the presence of such polarons significantly suppresses dissociation of water molecules that are bonded directly to polaronic sites. On the other hand, polarons facilitate water dissociation at certain nonpolaronic sites. Furthermore, polarons strengthen hydrogen bonds, which in turn affects water dissociation in hydrogen bonded overlayer structures. This study reveals that polarons at the rutile surface have complex, multifaceted, effects on water adsorption, dissociation and hydrogen bonding, highlighting the importance of polarons on water structure and dynamics on such surfaces. We expect that many of the physical properties of surface polarons identified here will apply more generally to surfaces and interfaces that can host small polarons, beyond titania.
Crosslists for Thu, 22 Aug 19
 [50] arXiv:1908.07540 (crosslist from hepth) [pdf, other]

Title: The negativity contour: a quasilocal measure of entanglement for mixed statesComments: 19 pages, 6 figuresSubjects: High Energy Physics  Theory (hepth); Statistical Mechanics (condmat.statmech); Strongly Correlated Electrons (condmat.strel); Quantum Physics (quantph)
In this paper, we study the entanglement structure of mixed states in quantum manybody systems using the $\textit{negativity contour}$, a local measure of entanglement that determines which realspace degrees of freedom in a subregion are contributing to the logarithmic negativity and with what magnitude. We construct an explicit contour function for Gaussian states using the fermionic partialtranspose. We generalize this contour function to generic manybody systems using a natural combination of derivatives of the logarithmic negativity. Though the latter negativity contour function is not strictly positive for all quantum systems, it is simple to compute and produces reasonable and interesting results. In particular, it rigorously satisfies the positivity condition for all holographic states and those obeying the quasiparticle picture. We apply this formalism to quantum field theories with a Fermi surface, contrasting the entanglement structure of Fermi liquids and holographic (hyperscale violating) nonFermi liquids. The analysis of nonFermi liquids show anomalous temperature dependence of the negativity depending on the dynamical critical exponent. We further compute the negativity contour following a quantum quench and discuss how this may clarify certain aspects of thermalization.
 [51] arXiv:1908.07570 (crosslist from qbio.SC) [pdf, other]

Title: How kinesin waits for ATP affects the nucleotide and load dependence of the stepping kineticsSubjects: Subcellular Processes (qbio.SC); Soft Condensed Matter (condmat.soft); Biological Physics (physics.bioph)
Dimeric molecular motors walk on polar tracks by binding and hydrolyzing one ATP per step. Despite tremendous progress, the waiting state for ATP binding in the wellstudied kinesin that walks on microtubule (MT), remains controversial. One experiment suggests that in the waiting state both heads are bound to the MT, while the other shows that ATP binds to the leading head after the partner head detaches. To discriminate between these two scenarios, we developed a theory to calculate accurately several experimentally measurable quantities as a function of ATP concentration and resistive force.
In particular, we predict that measurement of the randomness parameter could discriminate between the two scenarios for the waiting state of kinesin, thereby resolving this standing controversy.  [52] arXiv:1908.07583 (crosslist from mathph) [pdf, other]

Title: Entropy in Themodynamics: from Foliation to CategorizationAuthors: Radosław A. KyciaComments: 19 pages, 1 figure, a survey paper by no means an original research;Subjects: Mathematical Physics (mathph); Statistical Mechanics (condmat.statmech)
We overview the notion of entropy in thermodynamics. We start from the smooth case using differential forms on the manifold, which is the natural language for thermodynamics. Then the axiomatic definition of entropy as ordering on set that is induced by adiabatic processes will be outlined. Finally, the viewpoint of category theory is provided, which reinterprets the ordering structure as a category of preordered sets.
 [53] arXiv:1908.07588 (crosslist from physics.optics) [pdf]

Title: Improving indistinguishability of single photons from colloidal quantum dots using nanocavitiesSubjects: Optics (physics.optics); Mesoscale and Nanoscale Physics (condmat.meshall); Quantum Physics (quantph)
Colloidal quantum dots have garnered active research interest as quantum emitters due to their robust synthesis process and straightforward integration with nanophotonic platforms. However, obtaining indistinguishable photons from the colloidal quantum dots at room temperature is fundamentally challenging because they suffer from an extremely large dephasing rate. Here we propose an experimentally feasible method of obtaining indistinguishable single photons from an incoherently pumped solutionprocessed colloidal quantum dot coupled to a system of nanocavities. We show that by coupling a colloidal quantum dot to a pair of silicon nitride cavities, we can obtain comparable performance of a single photon source from colloidal quantum dots as other leading quantum emitters like defect centers and selfassembled quantum dots.
 [54] arXiv:1908.07595 (crosslist from mathph) [pdf, other]

Title: Connection probabilities in the doubledimer model  the case of two connectivity patternsAuthors: Nahid GhodratipourSubjects: Mathematical Physics (mathph); Statistical Mechanics (condmat.statmech)
We apply the Grassmannian representation of the dimer model, an equivalent approach to Kasteleyn's solution to the closepacked dimer problem, to calculate the connection probabilities for the doubledimer model with wired/free/wired/free boundary conditions, on a rectangular subdomain of the square lattice with four marked boundary points at the corners. Using some series identities related to SchwarzChristoffel transformations, we show that the continuum of the result is consistent with the corresponding one in the upper halfplane (previously obtained by KenyonWilson), which is in turn identical to the connection probabilities for 4SLE$_4$ emanating from the boundary, or equivalently, to a conditioned version of CLE$_4$ with wired/free/wired/free boundary conditions in the context of conformal loop ensembles.
 [55] arXiv:1908.07598 (crosslist from physics.optics) [pdf, other]

Title: Unitary Light2D matter Interaction and Universal Absorption in a Monolayer $\mbox{WS}_2$ Van der Waals Heterostructure CavityAuthors: Itai Epstein, Bernat Terres, Andre J. Chaves, VarunVarma Pusapati, Daniel A. Rhodes, Bettina Frank, Valentin Zimmermann, Ying Qin, Kenji Watanabe, Takashi Taniguchi, Harald Giessen, Sefaattin Tongay, James C. Hone, Nuno M. R. Peres, Frank KoppensSubjects: Optics (physics.optics); Mesoscale and Nanoscale Physics (condmat.meshall)
A direct bandgap and large exciton binding energies provide an optical response dominated by excitons in monolayer transitionmetaldichalcogenides (TMDs). While various approaches have been applied to lightexciton interaction in TMDs, the achieved strength have been far below unity, and a complete picture of its underlying physical mechanisms and fundamental limits has not been provided. Here, we introduce a TMDbased Van der Waals heterostructure cavity that provides unitary excitonic absorption, and excitonic complexes emission that are observed at ultralow excitation powers. Our results are in full agreement with a quantum theoretical framework introduced to describe the lightexcitoncavity interaction. We find that the subtle interplay between the radiative, nonradiative and dephasing decay rates plays a crucial role, and unveil a universal absorption law for excitons in 2Dsystems. This enhanced lightexciton interaction paves the way to new possibilities for 2D semiconductorsbased optoelectronic devices and allows more fundamental studies on phasetransitions of excitonic complexes.
 [56] arXiv:1908.07637 (crosslist from quantph) [pdf, other]

Title: Universal gates for protected superconducting qubits using optimal controlAuthors: Mohamed Abdelhafez, Brian Baker, Andras Gyenis, Pranav Mundada, Andrew A. Houck, David Schuster, Jens KochComments: 12 pages, 6 figuresSubjects: Quantum Physics (quantph); Mesoscale and Nanoscale Physics (condmat.meshall)
We employ quantum optimal control theory to realize quantum gates for two protected superconducting circuits: the heavyfluxonium qubit and the 0$\pi$ qubit. Utilizing automatic differentiation facilitates the simultaneous inclusion of multiple optimization targets, allowing one to obtain highfidelity gates with realistic pulse shapes. For both qubits, disjoint support of lowlying wave functions prevents direct population transfer between the computationalbasis states. Instead, optimal control favors dynamics involving higherlying levels, effectively lifting the protection for a fraction of the gate duration. For the 0$\pi$ qubit, offsetcharge dependence of matrix elements among higher levels poses an additional challenge for gate protocols. To mitigate this issue, we randomize the offset charge during the optimization process, steering the system towards pulse shapes insensitive to charge variations. Closedsystem fidelities obtained are 99% or higher, and show slight reductions in opensystem simulations.
 [57] arXiv:1908.07661 (crosslist from physics.appph) [pdf]

Title: Designing Anisotropic Microstructures with Spectral Density FunctionAuthors: Akshay Iyer, Rabindra Dulal, Yichi Zhang, Umar Farooq Ghumman, TeYu Chien, Ganesh Balasubramanian, Wei ChenSubjects: Applied Physics (physics.appph); Materials Science (condmat.mtrlsci)
Materials' microstructure strongly influences its performance and is thus a critical aspect in design of functional materials. Previous efforts on microstructure mediated design mostly assume isotropy, which is not ideal when material performance is dependent on an underlying transport phenomenon. In this article, we propose an anisotropic microstructure design strategy that leverages Spectral Density Function (SDF) for rapid reconstruction of high resolution, two phase, isotropic or anisotropic microstructures in 2D and 3D. We demonstrate that SDF microstructure representation provides an intuitive method for quantifying anisotropy through a dimensionless scalar variable termed anisotropy index. The computational efficiency and low dimensional microstructure representation enabled by our method is demonstrated through an active layer design case study for Bulk Heterojunction Organic Photovoltaic Cells (OPVCs). Results indicate that optimized design, exhibiting strong anisotropy, outperforms isotropic active layer designs. Further, we show that Crosssectional Scanning Tunneling Microscopy and Spectroscopy (XSTM/S) is as an effective tool for characterization of anisotropic microstructures.
 [58] arXiv:1908.07685 (crosslist from physics.appph) [pdf, other]

Title: Characterising Quantum Devices at Scale with Custom CryoCMOSAuthors: S. J. Pauka, K. Das, J. M. Hornibrook, G. C. Gardner, M. J. Manfra, M. C. Cassidy, D. J. ReillySubjects: Applied Physics (physics.appph); Mesoscale and Nanoscale Physics (condmat.meshall); Quantum Physics (quantph)
We make use of a customdesigned cryoCMOS multiplexer (MUX) to enable multiple quantum devices to be characterized in a single cooldown of a dilution refrigerator. Combined with a packaging approach that integrates cryoCMOS chips and a hotswappable, parallel device test platform, we describe how this setup takes a standard wiring configuration as input and expands the capability for batchcharacterization of quantum devices at milliKelvin temperatures and high magnetic fields. The architecture of the cryoCMOS multiplexer is discussed and performance benchmarked using fewelectron quantum dots and Hall mobilitymapping measurements.
 [59] arXiv:1908.07700 (crosslist from hepth) [pdf, other]

Title: Ishibashi States, Topological Orders with Boundaries and Topological Entanglement Entropy II  Cutting through the boundaryComments: 38 pages, 5 figuresSubjects: High Energy Physics  Theory (hepth); Strongly Correlated Electrons (condmat.strel); Quantum Physics (quantph)
We compute the entanglement entropy in a 2+1 dimensional topological order in the presence of gapped boundaries. Specifically, we consider entanglement cuts that cut through the boundaries. We argue that based on general considerations of the bulkboundary correspondence, the "twisted characters" feature in the Renyi entropy, and the topological entanglement entropy is controlled by a "halflinking number" in direct analogy to the role played by the Smodular matrix in the absence of boundaries. We also construct a class of boundary states based on the halflinking numbers that provides a "closedstring" picture complementing an "openstring" computation of the entanglement entropy. These boundary states do not correspond to diagonal RCFT's in general. These are illustrated in specific Abelian ChernSimons theories with appropriate boundary conditions.
 [60] arXiv:1908.07815 (crosslist from physics.appph) [pdf]

Title: Impact of a dopinginduced spacecharge region on the collection of photogenerated charge carriers in thinfilm solar cells based on lowmobility semiconductorsAuthors: Oskar J. Sandberg, Staffan Dahlström, Mathias Nyman, Sebastian Wilken, Dorothea Scheunemann, Ronald ÖsterbackaComments: Main text (29 pages, 7 figures) and supplemental material (7 pages, 4 figures)Subjects: Applied Physics (physics.appph); Materials Science (condmat.mtrlsci)
Unintentional doping of the active layer is a source for lowered device performance in organic solar cells. The effect of doping is to induce a spacecharge region within the active layer, generally resulting in increased recombination losses. In this work, the impact of a dopinginduced spacecharge region on the currentvoltage characteristics of lowmobility solar cell devices has been clarified by means of analytical derivations and numerical device simulations. It is found that, in case of a doped active layer, the collection efficiency of photogenerated charge carriers is independent of the light intensity and exhibits a distinct voltage dependence, resulting in an apparent electricfield dependence of the photocurrent. Furthermore, an analytical expression describing the behavior of the photocurrent is derived. The validity of the analytical model is verified by numerical driftdiffusion simulations and demonstrated experimentally on solutionprocessed organic solar cells. Based on the theoretical results, conditions of how to overcome charge collection losses caused by doping are discussed. Furthermore, the presented analytical framework provides tools to distinguish between different mechanisms leading to voltage dependent photocurrents.
 [61] arXiv:1908.07852 (crosslist from physics.appph) [pdf]

Title: Perfect proton selectivity in ion transport through twodimensional crystalsAuthors: L. Mogg, S. Zhang, G.P. Hao, K. Gopinadhan, D. Barry, B. L. Liu, H. M. Cheng, A. K. Geim, M. LozadaHidalgoSubjects: Applied Physics (physics.appph); Mesoscale and Nanoscale Physics (condmat.meshall)
Defectfree monolayers of graphene and hexagonal boron nitride were previously shown to be surprisingly permeable to thermal protons, despite being completely impenetrable to all gases. It remains untested whether small ions can permeate through the twodimensional crystals. Here we show that mechanically exfoliated graphene and hexagonal boron nitride exhibit perfect Nernst selectivity such that only protons can permeate through, with no detectable flow of counterions. In the experiments, we used suspended monolayers that had few if any atomicscale defects, as shown by gas permeation tests, and placed them to separate reservoirs filled with hydrochloric acid solutions. Protons accounted for all the electrical current and chloride ions were blocked. This result corroborates the previous conclusion that thermal protons can pierce defectfree twodimensional crystals. Besides importance for theoretical developments, our results are also of interest for research on various separation technologies based on twodimensional materials.
 [62] arXiv:1908.07863 (crosslist from math.PR) [pdf, other]

Title: Derivation of coupled KPZBurgers equation from multispecies zerorange processesSubjects: Probability (math.PR); Statistical Mechanics (condmat.statmech); Mathematical Physics (mathph)
We consider the fluctuation fields of multispecies weaklyasymmetric zerorange interacting particle systems in one dimension, where the mass density of each species is conserved. Although such fields have been studied in systems with a single species, the multispecies setting is much less understood. Among other results, we show that, when the system starts from stationary states, with a particular property, the scaling limits of the multispecies fluctuation fields, seen in a characteristic traveling frame, solve a coupled Burgers SPDE, which is a formal spatial gradient of a coupled KPZ equation.
 [63] arXiv:1908.07913 (crosslist from nlin.SI) [pdf, ps, other]

Title: On Bethe Ansatz for a Supersymmetric Vertex Model with $\mathcal{U}_{\rm q}[{\rm osp}(22)^{(2)}]$Comments: 18 pages. arXiv admin note: substantial text overlap with arXiv:hepth/9807219Subjects: Exactly Solvable and Integrable Systems (nlin.SI); Statistical Mechanics (condmat.statmech)
The Algebraic Bethe ansatz for a supersymmetric nineteen vertexmodel constructed from a threedimensional representation of the twisted quantum affine Lie superalgebra $\mathcal{U}_{q}[\mathrm{osp}(22)^{(2)}]$ is presented in detail. The eigenvalues and eigenvectors of the rowtorow transfer matrix are calculated and the corresponding Bethe Ansatz equations are obtained and analyzed numerically.
 [64] arXiv:1908.07944 (crosslist from nuclth) [pdf, ps, other]

Title: Critical endpoint and universality class of neutron $^3P_2$ superfluids in neutron starsComments: 14 pages, 5 figuresSubjects: Nuclear Theory (nuclth); Statistical Mechanics (condmat.statmech)
We study the thermodynamics and critical behavior of neutron $^3P_2$ superfluids in the inner cores of neutron stars. $^3P_2$ superfluids offer a rich phase diagram including uniaxial/biaxial nematic phases, the ferromagnetic phase, and the cyclic phase. Using the Bogoliubovde Gennes (BdG) equation as superfluid Fermi liquid theory, we show that a strong (weak) magnetic field drives the first (second) order transition from the dihedraltwo biaxial nematic phase to dihedralfour biaxial nematic phase in low (high) temperatures, and their phase boundaries are divided by the critical endpoint (CEP). We demonstrate that the set of critical exponents at the CEP satisfies the Rushbrooke, Griffiths, and Widom equalities, indicating a new universality class. At the CEP, the $^3P_2$ superfluid exhibits critical behavior with nontrivial critical exponents, indicating a new universality class. Furthermore, we find that the GinzburgLandau (GL) equation up to the 8thorder expansion satisfies three equalities and properly captures the physics of the CEP. This implies that the GL theory can provide a tractable way for understanding critical phenomena which may be realized in the dense core of realistic magnetars.
 [65] arXiv:1908.07954 (crosslist from nlin.AO) [pdf, other]

Title: Cross frequency coupling in next generation inhibitory neural mass modelsComments: 14 pages, 10 figuresSubjects: Adaptation and SelfOrganizing Systems (nlin.AO); Disordered Systems and Neural Networks (condmat.disnn)
Coupling among neural rhythms is one of the most important mechanisms at the basis of cognitive processes in the brain. In this study we consider a neural mass model, rigorously obtained from the microscopic dynamics of an inhibitory spiking network with exponential synapses, able to autonomously generate collective oscillations (COs). These oscillations emerge via a supercritical Hopf bifurcation, and their frequencies are controlled by the synaptic time scale, the synaptic coupling and the excitability of the neural population. Furthermore, we show that two inhibitory populations in a masterslave configuration with different synaptic time scales can display various collective dynamical regimes: namely, damped oscillations towards a stable focus, periodic and quasiperiodic oscillations, and chaos. Finally, when bidirectionally coupled the two inhibitory populations can exhibit different types of thetagamma crossfrequency couplings (CFCs): namely, phasephase and phaseamplitude CFC. The coupling between theta and gamma COs is enhanced in presence of a external theta forcing, reminiscent of the type of modulation induced in Hippocampal and Cortex circuits via optogenetic drive.
 [66] arXiv:1908.07958 (crosslist from quantph) [pdf, other]

Title: Efficient Encoding of Matrix Product States into Quantum Circuits of One and TwoQubit GatesAuthors: ShiJu RanComments: 6 pages, 5 figuresSubjects: Quantum Physics (quantph); Strongly Correlated Electrons (condmat.strel)
Matrix product state (MPS) belongs to the most important mathematical models in, for example, condensed matter physics and quantum information sciences. However, to realize an $N$qubit MPS with large $N$ and large entanglement on a quantum platform is extremely challenging, since it requires highlevel qudits or multibody gates of twolevel qubits to carry the entanglement. In this work, an efficient method that accurately encodes a given MPS into a quantum circuit with only one and twoqubit gates is proposed. The idea is to construct the unitary matrix product operators that optimally disentangle the MPS to a product state. These matrix product operators form the quantum circuit that evolves a product state to the targeted MPS with a high fidelity. Our benchmark on the groundstate MPS's of the stronglycorrelated spin models show that the constructed quantum circuits can encode the MPS's with much fewer qubits than the sizes of the MPS's themselves. This method paves a feasible and efficient path to realizing quantum manybody states and other MPSbased models as quantum circuits on the nearterm quantum platforms.
 [67] arXiv:1908.07959 (crosslist from physics.compph) [pdf]

Title: Inverse Structural Design of Graphene/Boron Nitride Hybrids by Regressional GANSubjects: Computational Physics (physics.compph); Materials Science (condmat.mtrlsci); Applied Physics (physics.appph)
Inverse design of materials with desired properties is currently laborious and heavily relies on intuition of researchers through a trialanderror process. The massive combinational spaces due to the constituent elements and their structural configurations are too overwhelming to be all searched even by highthroughput computations. Herein, we demonstrated a novel regressional generative adversarial network (RGAN) for inverse design of representative twodimensional materials, graphene and boronnitride (BN) hybrids. A significant novelty of the proposed RGAN is that it combines the supervised and regressional convolutional neural network (CNN) with the traditional unsupervised GAN, thus overcoming the common technical barrier in the traditional GANs, which cannot generate data associated with given continuous quantitative labels. The proposed RGAN enables to autonomously generate graphene/BN hybrids with any given bandgaps. Moreover, the generated structures exhibit high fidelity, yielding bandgaps within ~ 10% MAEF of the desired bandgaps as crossvalidated by density functional theory (DFT) calculations. Further analysis by principle component analysis (PCA) and modified locally linear embedding (MLLE) methods on the latent features encoded by the regressor reveals that the generator has successfully generated structures that followed the statistical distribution of the real structures. It implies the possibility of the RGAN in recognizing physical rules hidden in the highdimensional data. This new inverse design methodology would speed up the discovery and development of other 2D materials and beyond.
 [68] arXiv:1908.07971 (crosslist from physics.fludyn) [pdf, other]

Title: Equilibrium and stability of twodimensional pinned dropsComments: 5 pages, 4 figuresSubjects: Fluid Dynamics (physics.fludyn); Soft Condensed Matter (condmat.soft)
Superhydrophobicity relies on the stability of drops's interfaces pinned on sharp edges to sustain nonwetting (CassieBaxter) equilibrium states. Gibbs already pointed out that equilibrium is possible as long as the pinning angle at the edge falls between the equilibrium contact angles corresponding to the flanks of the edge. However, the lack of stability can restrict further the realizable equilibrium configurations. To find these limits we analyze here the equilibrium and stability of twodimensional drops bounded by interfaces pinned on mathematically sharp edges. We are specifically interested on how the drop's stability depends on its size, which is measured with the Bond number $Bo = (\mathcal{W}_d/\ell_c)^2$, defined as the ratio of the drop's characteristic length scale $\mathcal{W}_d$ to the capillary length $\ell_c = \sqrt{\sigma/\rho g}$. Drops with a fixed volume become more stable as they shrink in size. On the contrary, open drops, i.e. capable of exchanging mass with a reservoir, are less stable as their associated Bond number decreases.
 [69] arXiv:1908.07989 (crosslist from hepth) [pdf, ps, other]

Title: Fractional Fermion Number and Hall Conductivity of Domain WallsComments: 9 pagesSubjects: High Energy Physics  Theory (hepth); Mesoscale and Nanoscale Physics (condmat.meshall)
In this letter the fractional fermion number of thick domain walls is computed. The analysis is achieved by developing the heat kernel expansion of the spectral eta functon of the Dirac Hamiltonian governing the fermionic fluctuations around the domain wall. A formula is derived showing that a non null fermion number is always accompanied by a Hall conductivity induced on the wall. In the limit of thin and impenetrable walls the chiral bag boundary conditions arise, and the Hall conductivity is computed for this case as well.
 [70] arXiv:1908.07991 (crosslist from physics.appph) [pdf, other]

Title: Prospects of designing goldnanoparticlesbased soft terahertz radiation sources and terahertztoinfrared converters for concealed object detection technologyComments: A manuscript for the SPIE Security+Defence 2019 conference, Strasbourg, Sep 912, 2019Subjects: Applied Physics (physics.appph); Mesoscale and Nanoscale Physics (condmat.meshall); Instrumentation and Detectors (physics.insdet)
The twophonon scheme of generation of terahertz (THz) photons by gold nanobars (GNBs) is considered. It is shown that in GNBs, by choosing their sizes, it is possible to provide conditions for converting the energy of longitudinal phonons with THz frequencies into the energy of THz photons. The prospects of designing GNBsbased soft THz radiation sources (frequencies: 0.14; 0.24; 0.41 and 0.70 THz) with a large flow crosssection (diameter ~40 cm) intended for detection of hidden objects under clothing to ensure security in public places (airports, railway stations, stadiums, etc.) are assessed. The choice of the above frequencies is a compromise between the requirements of low absorption of THz radiation by water vapor in air, good penetration through the fabric of clothing, favoring a sufficient resolution of the imaging system, and an abundance of corresponding longitudinal phonons, capable of exciting Fermi electrons in GNBs. Estimates of the characteristics of the terahertztoinfrared converter based on gold nanospheres (GNSs), which could work in tandem with these sources of THz radiation  as a means of visualization of hidden objects  are also given.
Replacements for Thu, 22 Aug 19
 [71] arXiv:1802.08763 (replaced) [pdf, other]

Title: BerezinskiiKosterlitzThouless transition of twocomponent Bose mixtures with intercomponent Josephson couplingComments: 11 pages, 9 figuresJournalref: Phys. Rev. Lett. 123, 075303 (2019)Subjects: Statistical Mechanics (condmat.statmech); Superconductivity (condmat.suprcon); High Energy Physics  Theory (hepth)
 [72] arXiv:1803.07282 (replaced) [pdf]

Title: Observation of Rydberg exciton polaritons and their condensate in a perovskite cavityAuthors: Wei Bao, Xiaoze Liu, Fei Xue, Fan Zheng, Renjie Tao, Siqi Wang, Yang Xia, Mervin Zhao, Jeongmin Kim, Sui Yang, Quanwei Li, Ying Wang, Yuan Wang, LinWang Wang, Allan MacDonald, Xiang ZhangSubjects: Materials Science (condmat.mtrlsci); Mesoscale and Nanoscale Physics (condmat.meshall)
 [73] arXiv:1807.08245 (replaced) [pdf, other]

Title: Continuous transformation between ferro and antiferro circular structures in $J_1J_2J_3$ frustrated Heisenberg modelComments: 9 pages, 12 figuresJournalref: Journal of Physics: Condensed Matter, Volume 31, Number 45 (2019)Subjects: Disordered Systems and Neural Networks (condmat.disnn); Statistical Mechanics (condmat.statmech); Strongly Correlated Electrons (condmat.strel)
 [74] arXiv:1809.07985 (replaced) [pdf, ps, other]

Title: Thermodynamic properties of ferroics described by the transverse Ising model and their applications for CoNb$_2$O$_6$Comments: 22 pages, 16 figuresSubjects: Strongly Correlated Electrons (condmat.strel)
 [75] arXiv:1810.00698 (replaced) [pdf, other]

Title: An operational approach to quantum stochastic thermodynamicsAuthors: Philipp StrasbergComments: Postfinal version with Eq. (28) corrected compared to the published versionJournalref: Phys. Rev. E 100, 022127 (2019)Subjects: Quantum Physics (quantph); Statistical Mechanics (condmat.statmech)
 [76] arXiv:1810.03211 (replaced) [pdf, other]

Title: Gazing at crystal balls  Electron backscatter diffraction indexing and cross correlation on a sphereComments: Resubmitted version (submitted for review 21/08/2019)Subjects: Materials Science (condmat.mtrlsci)
 [77] arXiv:1901.05201 (replaced) [pdf, other]

Title: Enhancing power grid synchronization and stability through time delayed feedback controlSubjects: Adaptation and SelfOrganizing Systems (nlin.AO); Disordered Systems and Neural Networks (condmat.disnn); Chaotic Dynamics (nlin.CD)
 [78] arXiv:1901.05709 (replaced) [pdf, other]

Title: Linear response theory for quantum Gaussian processesComments: Close to the published versionJournalref: New J. Phys. 21 083036 (2019)Subjects: Statistical Mechanics (condmat.statmech); Quantum Physics (quantph)
 [79] arXiv:1901.11495 (replaced) [pdf, other]

Title: Modelling microgels with controlled structure across the volume phase transitionAuthors: Andrea Ninarello, Jérôme J. Crassous, Divya Paloli, Fabrizio Camerin, Nicoletta Gnan, Lorenzo Rovigatti, Peter Schurtenberger, Emanuela ZaccarelliSubjects: Soft Condensed Matter (condmat.soft)
 [80] arXiv:1902.00210 (replaced) [pdf, other]

Title: BerezinskiiKosterlitzThouless transition of spin1 spinor Bose gases in the presence of the quadratic Zeeman effectAuthors: Michikazu KobayashiComments: 15 pages, 19 figuresJournalref: J. Phys. Soc. Jpn. 88 094001 (2019)Subjects: Quantum Gases (condmat.quantgas); Statistical Mechanics (condmat.statmech)
 [81] arXiv:1902.06295 (replaced) [pdf, other]

Title: Electrical writing, deleting, reading, and moving of magnetic skyrmioniums in a racetrack deviceComments: This is a postpeerreview, precopyedit version of an article published in Scientific Reports. The final authenticated version is available online at [DOI]Journalref: Scientific Reports 9, 12119 (2019)Subjects: Strongly Correlated Electrons (condmat.strel); Mesoscale and Nanoscale Physics (condmat.meshall)
 [82] arXiv:1902.08540 (replaced) [pdf, other]

Title: On the preparation and NMR spectroscopic characterization of potassium aluminium tetrahydride KAlH4Comments: 27 pages, 5 figures, final version as published in PCCP, with reviewer reports attached to the ESISubjects: Materials Science (condmat.mtrlsci)
 [83] arXiv:1903.10499 (replaced) [pdf, other]

Title: Slow scrambling and hidden integrability in a random rotor modelComments: 5+6 pages, 3+2 figuresSubjects: Strongly Correlated Electrons (condmat.strel); Statistical Mechanics (condmat.statmech); High Energy Physics  Theory (hepth)
 [84] arXiv:1903.10733 (replaced) [pdf, ps, other]

Title: Drastic enhancement of the thermal Hall angle in a $d$wave superconductorComments: 10 pages, 11 figuresSubjects: Superconductivity (condmat.suprcon)
 [85] arXiv:1903.11545 (replaced) [pdf, other]

Title: Datadriven, structurebased hyperelastic manifolds: A macromicromacro approachSubjects: Materials Science (condmat.mtrlsci)
 [86] arXiv:1904.02042 (replaced) [pdf, other]

Title: OntheFly Bayesian Active Learning of Interpretable ForceFields for Atomistic Rare EventsSubjects: Computational Physics (physics.compph); Materials Science (condmat.mtrlsci)
 [87] arXiv:1904.05909 (replaced) [pdf]

Title: Excitonic and lattice contributions to the charge density wave in 1TTiSe$_2$ revealed by a phonon bottleneckAuthors: Hamoon Hedayat, Charles J. Sayers, Davide Bugini, Claudia Dallera, Daniel Wolverson, Tim Batten, Sara Karbassi, Sven Friedemann, Giulio Cerullo, Jasper van Wezel, Stephen R. Clark, Ettore Carpene, Enrico Da ComoComments: 11 pages, 4 figuresSubjects: Strongly Correlated Electrons (condmat.strel); Mesoscale and Nanoscale Physics (condmat.meshall); Materials Science (condmat.mtrlsci)
 [88] arXiv:1904.13152 (replaced) [pdf, other]

Title: Nonuniversal Transverse Electron Mean Free Path through Fewlayer GrapheneJournalref: Phys. Rev. Lett. 123, 086802 (2019)Subjects: Materials Science (condmat.mtrlsci); Mesoscale and Nanoscale Physics (condmat.meshall)
 [89] arXiv:1905.03437 (replaced) [pdf, other]

Title: Intervention Threshold for Epidemic Control in SusceptibleInfectedRecovered Metapopulation ModelsComments: 11pages, 8 figuresJournalref: Phys. Rev. E 100, 022302 (2019)Subjects: Physics and Society (physics.socph); Statistical Mechanics (condmat.statmech)
 [90] arXiv:1905.03898 (replaced) [pdf, other]

Title: Prediction of thermal conductivity in dielectrics using fast, spectrallyresolved phonon transport simulationsComments: 36 pages, 13 figuresSubjects: Materials Science (condmat.mtrlsci); Mesoscale and Nanoscale Physics (condmat.meshall); Computational Physics (physics.compph)
 [91] arXiv:1905.05782 (replaced) [pdf, other]

Title: Disentangling Sources of Quantum Entanglement in Quench DynamicsComments: Updated version with minor modificationsJournalref: Phys. Rev. Research 1, 012007(R) (2019)Subjects: Strongly Correlated Electrons (condmat.strel); Statistical Mechanics (condmat.statmech); Quantum Physics (quantph)
 [92] arXiv:1905.06901 (replaced) [pdf, ps, other]

Title: Coexistence of ferromagnetic fluctuations and superconductivity in the actinide superconductor UTe2Authors: Shyam Sundar, S. Gheidi, K. Akintola, A. M. Cote, S. R. Dunsiger, S. Ran, N. P. Butch, S. R. Saha, J. Paglione, J. E. SonierComments: 5 pages, 6 figuresSubjects: Superconductivity (condmat.suprcon)
 [93] arXiv:1905.08906 (replaced) [pdf, other]

Title: Transport and spectral signatures of transient fluctuating superfluids in the absence of longrange orderComments: 25 pages, 5 figuresSubjects: Superconductivity (condmat.suprcon)
 [94] arXiv:1905.11696 (replaced) [pdf, other]

Title: Computing threedimensional densities from force densities improves statistical efficiencyComments: Main paper 13 pages 8 figures. Supporting information 2 pages 4 figures. Published in the Journal of Chemical PhysicsJournalref: J. Chem. Phys. 151 (2019) 064124Subjects: Chemical Physics (physics.chemph); Statistical Mechanics (condmat.statmech)
 [95] arXiv:1906.05307 (replaced) [pdf, other]

Title: Universal shift of the fidelity susceptibility peak away from the critical point of the BerezinskiiKosterlitzThouless quantum phase transitionComments: published version, 6 pages, 2 figuresJournalref: Phys. Rev. B 100 081108(R) (2019)Subjects: Statistical Mechanics (condmat.statmech); Strongly Correlated Electrons (condmat.strel)
 [96] arXiv:1907.00018 (replaced) [pdf, ps, other]

Title: Percolation of sites not removed by a random walker in $d$ dimensionsComments: RevTex, 12 pages, 13 figuresJournalref: Phys. Rev. E 100, 022125 (2019)Subjects: Statistical Mechanics (condmat.statmech)
 [97] arXiv:1907.00291 (replaced) [pdf, other]

Title: Logarithmic growth of local entropy and total correlations in manybody localized dynamicsComments: 4 pages, 5 figures, comments are welcomeSubjects: Quantum Physics (quantph); Statistical Mechanics (condmat.statmech)
 [98] arXiv:1907.08204 (replaced) [pdf, other]

Title: Topological theory of LiebSchultzMattis theorems in quantum spin systemsComments: 27 pages + 12 pages of appendices. v2 updated referencesSubjects: Strongly Correlated Electrons (condmat.strel); Mathematical Physics (mathph); Quantum Physics (quantph)
 [99] arXiv:1907.10784 (replaced) [pdf]

Title: PhaseChange Control of Interlayer Exchange CouplingAuthors: Xiaofei Fan, Guodong Wei, Xiaoyang Lin, Xinhe Wang, Zhizhong Si, Xueying Zhang, Qiming Shao, Stephane Mangin, Eric Fullerton, Lei Jiang, Weisheng ZhaoSubjects: Materials Science (condmat.mtrlsci)
 [100] arXiv:1907.11602 (replaced) [pdf]

Title: Time Reversal Symmetry Breaking in the FeChalcogenide SuperconductorsSubjects: Superconductivity (condmat.suprcon)
 [101] arXiv:1908.03292 (replaced) [pdf, other]

Title: Out of Time Order Correlations in the QuasiPeriodic AubryAndré modelComments: 14 pages, 10 figuresSubjects: Statistical Mechanics (condmat.statmech); Disordered Systems and Neural Networks (condmat.disnn); Quantum Physics (quantph)
 [102] arXiv:1908.04257 (replaced) [pdf, ps, other]

Title: Phonon traps reduce the quasiparticle density in superconducting circuitsAuthors: Fabio Henriques, Francesco Valenti, Thibault Charpentier, Marc Lagoin, Clement Gouriou, Maria Martínez, Laura Cardani, Marco Vignati, Lukas Grünhaupt, Daria Gusenkova, Julian Ferrero, Sebastian T. Skacel, Wolfgang Wernsdorfer, Alexey V. Ustinov, Gianluigi Catelani, Oliver Sander, Ioan M. PopSubjects: Superconductivity (condmat.suprcon)
 [103] arXiv:1908.04536 (replaced) [pdf, other]

Title: Phase structure of the 1+1 dimensional massive Thirring model from matrix product statesAuthors: Mari Carmen Bañuls, Krzysztof Cichy, YingJer Kao, C.J. David Lin, YuPing Lin, David T.L. TanComments: 30 pages, 18 figures; minor stylistic changes, typos corrected, references addedSubjects: High Energy Physics  Lattice (heplat); Strongly Correlated Electrons (condmat.strel); High Energy Physics  Theory (hepth); Quantum Physics (quantph)
 [104] arXiv:1908.06101 (replaced) [pdf, other]

Title: Parallel implementation of highfidelity multiqubit gates with neutral atomsAuthors: Harry Levine, Alexander Keesling, Giulia Semeghini, Ahmed Omran, Tout T. Wang, Sepehr Ebadi, Hannes Bernien, Markus Greiner, Vladan Vuletić, Hannes Pichler, Mikhail D. LukinComments: 6 pages, 4 figures + Supplemental Materials (10 pages, 6 figures)Subjects: Quantum Physics (quantph); Quantum Gases (condmat.quantgas)
 [105] arXiv:1908.06578 (replaced) [pdf, other]

Title: Ultraviolet to Nearinfrared Single Photon Emitters in hBNAuthors: QingHai Tan, XueLu Liu, Dan Guo, YongZhou Xue, ShuLiang Ren, YuanFei Gao, XiuMing Dou, BaoQuan Sun, HuiXiong Deng, PingHeng Tan, Jun ZhangComments: 5 FiguresSubjects: Applied Physics (physics.appph); Materials Science (condmat.mtrlsci); Optics (physics.optics)
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