查看更多>>摘要：Abstract Molecular dynamics and Monte Carlo methods are common measurements to study the diffusion coefficients of the fluid particles under restricted conditions. Here, the collective diffusion coefficient will be obtained through two methods: the one is Fick’s first law (direct mode), and the other is the relationship between collective diffusion coefficient and self-diffusion coefficient (indirect mode). A comparison between two methods is also discussed. The ways of calculation, which are applied for the self-diffusion coefficient and collective diffusion coefficient, are helpful for studying transport characteristics of various molecules in defined space.Graphical abstract In this manuscript, we have reported the collective diffusion coefficient obtained through two methods: Fick’s first law (direct mode, as shown in Fig. 1) and the relationship between collective diffusion coefficient and self-diffusion coefficient (indirect mode, as shown in Fig. 2). It is shown that the two methods are accessible and each has their advantages and disadvantages.
查看更多>>摘要：Abstract Using dynamical mean-field theory we explore the electronic properties of the bilayer Hubbard model. For realistic model parameters we find a large reduction of the bonding-antibonding splitting of pure and hole doped Bi2\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$_2$$\end{document}Sr2\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$_2$$\end{document}CaCu2\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$_2$$\end{document}O8+δ\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$_{8 +\delta }$$\end{document} bilayer superconductor due to sizable dynamical correlations. Our results reveal a remarkable layer-selective renormalization of the Cu-3d bands caused by the interplay of intralayer Coulomb interaction and layer polarization with emergent Landau–Fermi liquid electronic excitations. At finite repulsive interlayer Coulomb interaction we predict a continuous layer decoupling phenomenon with coexisting Landau–Fermi liquid and Mott localized electrons. The emergence of layer-selectivity is important for the ongoing debate of correlated two-fluid superconductivity.Graphical abstract
查看更多>>摘要：Abstract The Ensemble of trajectories x(0≤t≤T)\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$x(0 \le t \le T)$$\end{document} produced by the Markov generator M in a discrete configuration space can be considered as ‘Canonical’ for the following reasons: (C1) the probability of the trajectory x(0≤t≤T)\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$x(0 \le t \le T)$$\end{document} can be rewritten as the exponential of a linear combination of its relevant empirical time-averaged observables En\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$E_n$$\end{document}, where the coefficients involving the Markov generator are their fixed conjugate parameters; (C2) the large deviations properties of these empirical observables En\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$E_n$$\end{document} for large T are governed by the explicit rate function IM[2.5](E.)\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$I^{[2.5]}_M (E_.) $$\end{document} at Level 2.5, while in the thermodynamic limit T=+∞\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$T=+\infty $$\end{document}, they concentrate on their typical values Entyp[M]\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$E_n^{typ[M]}$$\end{document} determined by the Markov generator M. This concentration property in the thermodynamic limit T=+∞\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$T=+\infty $$\end{document} suggests to introduce the notion of the ‘Microcanonical Ensemble’ at Level 2.5 for stochastic trajectories x(0≤t≤T)\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$x(0 \le t \le T)$$\end{document}, where all the relevant empirical variables En\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$E_n$$\end{document} are fixed to some values En?\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$E^*_n$$\end{document} and cannot fluctuate anymore for finite T. The goal of the present paper is to discuss its main properties: (MC1) when the long trajectory x(0≤t≤T)\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym}
查看更多>>摘要：Abstract We investigate Chinese BBS-Tianya Club collective users’ behaviors empirically and confirm that emerging attention on posts follows q-exponential novelty decay. We analytically derive a general model of reply asymptotic behavior, showing that the microscopic rate of change obeys the Gibrat proportional effect and q-exponential novelty decay. Rigorous statistical comparison and tests confirm that the empirically observed distribution of replies is subject to power-law distribution with an exponential cutoff, which is consistent with our theoretical analysis, suggesting that the proposed model effectively describes the collective replying dynamics on BBS.Graphical Abstract
查看更多>>摘要：Abstract In the framework of the Bogoliubov-de Gennes theory, we investigate the Majorana zero-energy states in mesoscopic superconducting square systems with spin–orbit (SO) interaction. The mixed d-wave and extended s-wave condensates as well as the favored s+id\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$s+id$$\end{document} state can be obtained by suitable choice of model parameters. We find that the energy gap is highly sensitive to the introduced SO interaction and the Majorana zero modes can emerge at four outer corners of a perfect square with only the Rashba SO interaction or with combined Rashba and Dresselhaus SO couplings. Furthermore, for a square sample with a centered hole, energy levels can cross the Fermi energy at appropriate Rashba SO-coupling strengths, accompanied with the occurrence of additional four Majorana corner states localized around the inner corners of the loop. The effect of Dresselhaus SO interaction on the number and location of Majorana corner states is also examined, and novel zero-energy modes mainly located at four opposite inner and outer corners along the (anti-)diagonal direction of the square loop can be realized.Graphical abstract
查看更多>>摘要：Abstract A novel second-order partial differential equation that describes the phase dynamics in the long Josephson junction and takes into account the flow of unpaired electrons across the junction is proposed. It has the form of the modified sine-Gordon equation with the nontrivial current–phase relation. The spatial behavior of the penetrated magnetic flux quantum (Josephson vortex or fluxon) is analyzed for the different values of the insulating layer transparency. The proposed equation of motion is used to investigate the dependence of the equilibrium fluxon velocity on the constant bias current for the different values of the insulating layer transparency. The self-consistent approach where the dissipation coefficient also depends on the layer transparency is applied. The resulting current–voltage characteristics (CVCs) have demonstrated better fluxon mobility for smaller values of the transparency coefficient.Graphic abstract
查看更多>>摘要：Abstract In many assembly line processes like metabolic and signaling networks in biological systems, the products of the first enzyme are the reactant for the next enzyme in the network. Working of multiple machines leads to efficient utilization of resources. Motivated by this, we investigate if multiple Maxwell demons lead to more efficient information processing. We study the phase space of multiple demons acting on an information tape based on the model of Mandal and Jarzynski [1, 2]. Their model is analytically solvable and the phase space of the device has three regions: engine, where work is delivered by writing information to the tape, erasure, where work is performed on the device to erase information on the tape, and dud, when work is performed and, at the same time, the information is written to the tape. For identical demons, we find that the erasure region increases at the expense of the dud region, while the information engine region does not change appreciably. The efficiency of the multiple demon device increases with the number of demons in the device and saturates to the equilibrium (maximum) efficiency even at short cycle times for very large numbers of demons. By investigating a device with non-identical demons acting on a tape, we identify the demon parameters that control the different regions of the phase space. Our model is well suited to study information processing in assembly line systems.Graphical abstract
查看更多>>摘要：Abstract We consider the motion of superconducting vortices and skyrmions on a square substrate near the first commensurate matching field. Slightly above commensuration, a series of dynamic phases appears including interstitial flow, and there is a transition from fluid flow to soliton flow that generates negative differential conductivity. Slightly below commensuration, vacancy depinning occurs. The dynamic phase transitions produce features in the velocity–force curves, differential mobility, and velocity fluctuations. In this work we have gone to much longer simulation times than in previous work, allowing us to examine the differential conductivity curves over a larger range of vortex and pinning densities. When a Magnus force is also present, as in certain superconducting vortex or skyrmion systems, there is an expansion of the fluid state, and at lower drives there is a finite Hall angle in the fluid phase but a vanishing Hall angle in the soliton phase, giving rise to a reentrant Hall effect. We also find a regime where the Hall motion of the particles exhibits the same dynamic phases, including soliton motion at a finite angle that produces negative differential conductivity in the Hall response but not in the longitudinal response. Our results suggest that vortices driven over periodic pinning may be an ideal system for determining if a vortex Hall effect is occurring and would also be relevant for skyrmions at smaller Magnus forces.Graphic abstract
查看更多>>摘要：Abstract We present a theoretical study of electronic transport in a two-dimensional 8-Pmmn monolayer borophene crystal illuminated by off-resonant electromagnetic radiation within the linear response theory. We find asymmetry in the intrinsic anomalous Hall conductivity of the system, hallmark of anisotropic tilted structure of the Dirac cones in borophene. The width of maximum in the Hall conductivity is of the order of the bandgap in the energy spectrum induced by the radiation. Interestingly, thermal and Peltier conductivities also exhibit pronounced asymmetry in addition to the Hall conductivity of the system. It is shown that such asymmetry in the conductivity originates from the anisotropic tilt in the Dirac cone of borophene. We also find that 8-Pmmn borophene makes transition from type-I to type-II Dirac fermion system in the limit of large tilt parameter.
查看更多>>摘要：Abstract The group delay time of Dirac fermions subjected to a tilting barrier potential along the x-axis is investigated in graphene. We start by finding the eigenspinor solution of the Dirac equation and then relating it to incident, reflected, and transmitted beam waves. This relationship allows us to compute the group delay time in transmission and reflection by obtaining the corresponding phase shifts. We discovered that the barrier width, incident energy, and incident angle can all be used to modify the group delay time, and that the particles travel through the barrier at the Fermi velocity vF\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ v_F $$\end{document}. Our findings also show that the transmission group delay might be controlled, and that gate voltage control could be useful in graphene-based tilting barriers.Graphical abstract FIG. 1. (color online) The group delay time in transmission tt/t0 as a function of the barrier width d for V0 = V1 = 80 meV, f = 30°\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$30^\circ $$\end{document} , E = 20 meV (blue line), E = 25 meV (red line), and E = 30 meV (green line).
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