arXiv subjects

Zhonghuai Hou

Publications and source records attributed to Zhonghuai Hou.

At least 19 recordsLinked to original sources

arXiv2026

Hierarchical Reconstruction of Time-arrow from Multi-time Correlations

The entropy production rate (EPR), a key measure of thermodynamic irreversibility in thermodynamics of small systems, is difficult to determine directly in experiments, motivating lower-bound-based estimation from observations. However, a systematic framework for organizing increasing amounts of the irreversibility information in experimental state observables into progressively tighter bounds remains lacking. Here, we show that multi-time correlations of a class of state observations naturally encode this information to provide a hierarchy. By defining a reconstruction operation as a combination of correlations, we obtain a sequence of lower bounds on the EPR. Correlations of higher order capture the thermodynamic information at greater temporal depth, thereby capturing more irreversibility and yielding tighter bounds. Under ideal conditions, this hierarchy converges to the full EPR in the limit of infinitely dense observations over a finite time window.

cond-mat.stat-mech↗

arXiv2026

Steering Active-Colloid Assembly by Biasing Dissipation

Complex nonequilibrium self-assembly enables the formation of materials with specific patterns and functions from the bottom up. How to directionally control the assembly to form the target configuration is a challenge. Here, we propose a dissipation bias principle for targeted assembly, which highlights that controlling the dissipation tendency can play an important role by modulating the frequency and intensity of local rearrangements. Following this principle, one can induce ordered target configurations from disordered structures and also achieve directional selection among multiple assembly pathways. We use the assembly of active colloids as a platform to show our results.

cond-mat.soft↗

arXiv2025

Universal trade-off between irreversibility and intrinsic timescale in thermal relaxation with applications to thermodynamic inference

We establish a general lower bound for the entropy production rate (EPR) based on the Kullback-Leibler divergence and the Logarithmic-Sobolev constant that characterizes the time-scale of relaxation. This bound can be considered as an enhanced second law of thermodynamics. When applied to thermal relaxation, it reveals a universal trade-off relation between the dissipation rate and the intrinsic relaxation timescale. From this relation, a thermodynamic upper bound on the relaxation time between two given states emerges, acting as an inverse speed limit over the entire time region. We also obtain a quantum version of this upper bound, which is always tighter than its classical counterpart, incorporating an additional term due to decoherence. Remarkably, we further demonstrate that the trade-off relation remains valid for any generally non-Markovian coarse-grained relaxation dynamics, highlighting its significant applications in thermodynamic inference. This trade-off relation is a new tool in inferring EPRs in molecular dynamics simulations and practical experiments.

cond-mat.stat-mech↗

arXiv2025

Accelerating Quantum Relaxation via Temporary Reset: A Mpemba-Inspired Approach

Slow relaxation processes spanning widely separated timescales pose fundamental challenges for probing steady-state properties and engineering functional quantum systems, such as quantum heat engines and quantum computing devices. We introduce a protocol that enables significant acceleration of relaxation in general Markovian open quantum systems by temporarily coupling the system to a reset channel, inspired by the Mpemba effect. Crucially, this acceleration persists even when the slowest decaying Lindbladian modes form complex-conjugate pairs. Unlike previous approaches, which typically target a single mode, our protocol may suppress multiple relaxation modes simultaneously. This framework provides a versatile and experimentally feasible tool for controlling relaxation timescales, with broad implications for quantum thermodynamics, computation, and state preparation.

quant-ph↗

arXiv2025

Noise-induced Quantum Mpemba effect

The quantum Mpemba effect (QMPE), an intriguing anomalous relaxation phenomenon, has recently attracted significant attention. However, how various types of noise, which are ubiquitous in real systems, may affect the QMPE remains unknown. Here, we address this gap by constructing a general dynamical framework for d level open quantum systems under random telegraph noise. By investigating the dynamics of an extended system and then projecting back, we find that noise can induce additional modes and strongly influence the relaxation dynamics of the original system. Specially, in the limit of long correlation time of noise, these modes cause anomalous slowdown for certain initial states, thereby inducing or eliminating QMPE, illustrated by a three-level example system. Interestingly, this mechanism leads to a counter intuitive effect:the decoherence rate may be slowed down by noise.

quant-ph↗

arXiv2025

Motorized Chromosome Models of Mitosis

During mitosis, near-spherical chromosomes reconfigure into rod-like structures to ensure their accurate segregation to daughter cells. We explore here, the interplay between the nonequilibrium activity of molecular motors in determining the chromosomal organization in mitosis and its characteristic symmetry-breaking events. We present a hybrid motorized chromosome model that highlights the distinct roles of condensin I and II in shaping mitotic chromosomes. Guided by experimental observations, the simulations suggest that condensin II facilitates large-scale scaffold formation, while condensin I is paramount in local helical loop arrangement. Together, these two distinct grappling motors establish the hierarchical helical structure characteristic of mitotic chromosomes, which exhibit striking local and, sometimes global, chirality and contribute to the robust mechanical properties of mitotic chromosomes. Accompanying the emergence of rigidity, the model provides mechanisms of forming defects, including perversions and entanglements, and shows how these may be partially resolved through condensin activity and topoisomerase action. This framework bridges coarse-grained energy landscape models of chromosome dynamics and non-equilibrium molecular dynamics, advancing the understanding of chromosome organization during cell division and beyond.

physics.bio-ph↗

arXiv2023

Effective diffusion of a tracer in active bath: a path-integral approach

We investigate the effective diffusion of a tracer immersed in an active particle bath consisting of self-propelled particles. Utilising the Dean's method developed for the equilibrium bath and extending it to the nonequilibrium situation, we derive a generalized Langevin equation (GLE) for the tracer particle. The complex interactions between the tracer and bath particles are shown as a memory kernel term and two colored noise terms. To obtain the effective diffusivity of the tracer, we use path integral technique to calculate all necessary correlation functions. Calculations show the effective diffusion decreases with the persistent time of active force, and has rich behavior with number density of bath particles, depending on different activity. All theoretical results regarding the dependence of such diffusivity on bath parameters have been confirmed by direct computer simulation.

cond-mat.soft↗

arXiv2023

Improving estimation of entropy production rate for run-and-tumble particle systems by high-order thermodynamic uncertainty relation

Entropy production plays an important role in the regulation and stability of active matter systems, and its rate quantifies the nonequilibrium nature of these systems. However, entropy production is hard to be experimentally estimated even in some simple active systems like molecular motors or bacteria, which may be modeled by the run-and-tumble particle (RTP), a representative model in the study of active matters. Here we resolve this problem for an asymmetric RTP in one-dimension, firstly constructing a finite time thermodynamic uncertainty relation (TUR) for a RTP, which works well in the short observation time regime for entropy production estimation. Nevertheless, when the activity dominates,i.e., the RTP is far from equilibrium, the lower bound for entropy production from TUR turns to be trivial. We address this issue by introducing a recently proposed high-order thermodynamic uncertainty relation (HTUR), in which the cumulant generating function of current serve as a key ingredient. To exploit the HTUR, we adopt a novel method to analytically obtain the cumulant generating function of the current we study, with no need to explicitly know the time-dependent probability distribution. The HTUR is demonstrated to be able to estimate the steady state energy dissipation rate accurately because the cumulant generating function covers higher-order statistics of the current, including rare and large fluctuations besides its variance. Compared to the conventional TUR, the HTUR could give significantly improved estimation of energy dissipation, which can work well even in the far-from equilibrium regime. We also provide a strategy based on the improved bound to estimate the entropy production from moderate amount of trajectory data for experimental feasibility.

cond-mat.stat-mech↗

arXiv2022

Unraveling on Kinesin Acceleration in Intracellular Environments: A Theory for Active Bath

Single molecular motor kinesin harnesses thermal and non-thermal fluctuations to transport various cargoes along microtubules, converting chemical energy to directed movements. To describe the non-thermal fluctuations generated by the complex environment in living cells, we establish a bottom-up model to mimic the intracellular environment, by introducing an active bath consisting of active Ornstein-Uhlenbeck (OU) particles. Simulations of the model system show that kinesin and the probe attached to it are accelerated by such active bath. Further, we provide a theoretical insight into the simulation result by deriving a generalized Langevin equation (GLE) for the probe with a mean-field method, wherein an effective friction kernel and fluctuating noise terms are obtained explicitly. Numerical solutions of the GLE show very good agreement with simulation results. We sample such noises, calculate their variances and non-Gaussian parameters, and reveal that the dominant contribution to probe acceleration is attributed to noise variance.

cond-mat.soft↗

arXiv2022

Dynamic and Thermodynamic Origins of Motility-Induced Phase Separation

Active matter systems are inherently out of equilibrium and break the detailed balance (DB) at the microscopic scale, exhibiting vital collective phenomena such as motility-induced phase separation (MIPS). Here, we introduce a coarse-grained mapping method to probe DB breaking in the density-energy phase space, which allows us to reveal the dynamic and thermodynamic origins of MIPS based on nonequilibrium potential and flux landscape theory. Hallmarks of nonequilibrium properties are manifested by identifying the visible probability flux in the coarse-grained phase space. Remarkably, the flux for the system with the activity lower than the MIPS threshold tends to ``tear up" the single potential well of the uniform-density phase to create two wells of phases with different densities, presenting directly that the nonequilibrium flux is the dynamic origin of MIPS. Moreover, we find that the obtained entropy production rate (EPR) of the system undergoes a transition from nearly independent of activity to increasing proportionally as activity increases after the single well is "teared up". The transition of EPR's scaling behavior might provide a hint of the thermodynamic origin of MIPS in the coarse-grained space. Our findings propose a new route to explore the nonequilibrium nature of active systems, and provide new insights into dynamic and thermodynamic properties of MIPS.

cond-mat.soft↗

arXiv2022

Fast Functionalization with High Performance in the Autonomous Information Engine

Mandal and Jarzynski have proposed a fully autonomous information heat engine, consisting of a demon, a mass and a memory register interacting with a thermal reservoir. This device converts thermal energy into mechanical work by writing information to a memory register, or conversely, erasing information by consuming mechanical work. Here, we derive a speed limit inequality between the relaxation time of state transformation and the distance between the initial and final distributions, where the combination of the dynamical activity and entropy production plays an important role. Such inequality provides a hint that a speed-performance trade-off relation exists between the relaxation time to functional state and the average production. To obtain fast functionalization while maintaining the performance, we show that the relaxation dynamics of information heat engine can be accelerated significantly by devising an optimal initial state of the demon. Our design principle is inspired by the so-called Mpemba effect, where water freezes faster when initially heated.

cond-mat.stat-mech↗

arXiv2022

Designing Autonomous Maxwell Demon via Stochastic Resetting

Autonomous Maxwell demon is a new type of information engine proposed by Mandal and Jarzynski, which can produce work by exploiting an information tape. Here, we show that a stochastic resetting mechanism can be used to improve the performance of autonomous Maxwell demons notably. Generally, the performance is composed of two important features, the time cost for an autonomous demon to reach its functional state and its efficacious working region in its functional state. Here, we provide a set of design principles for the system, which are capable of improving the two important features. On the one hand, one can drive any autonomous demon system to its functional periodic steady state at a fastest pace for any initial distribution through resetting the demon for a predetermined critical time and closing the reset after that. On the other hand, the system can reach a new functional state when the resetting is always on, in which case the efficacious region of the demon being extended significantly. Moreover, a dual function region in a new phase diagram of the demon with resetting has been found. Remarkably, in this dual function region the demon with resetting can realize anomalous output of work and erasure of information on the tape simultaneously, violating the second law of thermodynamics apparently. To this question, we derive a new modified Clausius inequality to restore the second law by taking the cost of resetting into account.

cond-mat.stat-mech↗

arXiv2022

Improved estimation for energy dissipation in biochemical oscillations

Biochemical oscillations, regulating the timing of life processes, need consume energy to achieve good performance on crucial functions, such as high accuracy of phase period and high sensitivity to external signals. However, it is a great challenge to precisely estimate the energy dissipation in such systems. Here, based on the stochastic normal form theory (SNFT), we calculate the Pearson correlation coefficient between the oscillatory amplitude and phase, and a trade-off relation between transport efficiency and phase sensitivity can then be derived, which serves as a tighter form than the estimator resulting from the conventional thermodynamic uncertainty relation (TUR). Our findings demonstrate that a more precise energy dissipation estimation can be obtained by enhancing the sensitivity of the biochemical oscillations. Moreover, the internal noise and amplitude power effects have also been discovered.

cond-mat.stat-mech↗

arXiv2022

Effective Entropy Production and Thermodynamic Uncertainty Relation of Active Brownian Particles

Understanding stochastic thermodynamics of active Brownian particles (ABPs) system has been an important topic in very recent years. In this article we study a general model of active Brownian particle systems by introducing a coarse-grained Fokker-Planck equation, which allows us to identify an effective entropy production along a stochastic trajectory, wherein an activity and configuration dependent diffusion coefficient comes into play with an important role. Although the hidden component between the true entropy production and the effective one is dominant, the effective entropy production still act as a reliable measure to quantify the dynamical irreversibility, capturing important phenomenon such as the interface and defects of motility induced phase separation (MIPS). Furthermore, in this framework, we are able to obtain the entropic bound as well as TUR associated with any generalized currents in the systems. We expect the new conceptual quantities proposed here to be broadly used in the context of active matter.

cond-mat.stat-mech↗

arXiv2022

Activity-induced Nonequilibrium Vaporization Leads to Reentrant Phase Separation

Active Brownian particles (ABPs) with pure repulsion is an ideal model to understand the effect of nonequilibrium on collective behaviors. It has long been established that activity can create effective attractions leading to motility-induced phase separation (MIPS), whose role is similar to that of (inverse) temperature in the simplest equilibrium system with attractive inter-particle interactions. Here, our theoretical analysis based on a kinetic theory of MIPS shows that a new type of activity-induced nonequilibrium vaporization is able to hinder the formation of dense phase when activity is large enough. Such nonequilibrium vaporization along with the activity-induced effective attraction thus lead to a MIPS reentrance. Numerical simulations verify such nonequilibrium effect induced solely by activity on phase behaviors of ABPs, and further demonstrate the dependence of MIPS on activity and the strength of inter-particle interaction predicted by our theoretical analysis. Our findings highlight the unique role played by the nonequilibrium nature of activity on phase behaviors of active systems, which may inspire deep insights into the essential difference between equilibrium and nonequilibrium systems.

cond-mat.soft↗

arXiv2021

Designing circle Swimmers: Principles and strategies

Various microswimmers move along circles rather than straight lines due to their swimming mechanisms, body shapes or hydrodynamic effects. Here, we adopt the concepts of stochastic thermodynamics to analyze circle swimmers confined in a two-dimensional plane, and study the trade-off relations between various physical quantities such as precision, energy cost and rotational speed. Based on these findings, we predict principles and strategies for designing microswimmers of special optimized functions under limited energy resource conditions, which will bring new experimental inspiration for designing smart motors.

cond-mat.soft↗

arXiv2021

Effective Dynamics of Tracer in Active Bath: A Mean-field Theory Study

We develop a theoretical framework to study the effective dynamics of a tracer immersed in a nonequilibrium bath consisting of active particles. By using a mean-field approximation and extending the linearized Dean equation to nonequilibrium environment, we derive a generalized Langevin equation for the tracer particle, wherein colored noise terms and a memory kernel reflect the roles of interactions between tracer and bath particles as well as activity of the bath. In particular, we obtain a self-consistent equation to calculate the long time diffusion coefficient and mobility of tracer, finding that they both increase non-linearly with bath activity, in good consistents with direct simulation results.

cond-mat.stat-mech↗

arXiv2020

Inertial Effects on Kinetics of Motility-Induced Phase Separation

Motility-induced phase separation (MIPS) is of great importance and has been extensively researched in overdamped systems, nevertheless, what impacts inertia will bring on kinetics of MIPS is lack of investigation. Here, we find that, not only the phase transition changes from continuous to discontinuous, but also the formation of clusters exhibits a nucleation-like process without any coarsening regime, different from spinodal decomposition in the overdamped case. This remarkable kinetics stems from a competition between activity-induced accumulation of particles and inertia-induced suppression of clustering process. More interestingly, the discontinuity of MIPS still exists even when the ratio of particle mass to the friction coefficient reduces to be very small such as 0.0001. Our findings emphasize the importance of inertia in kinetics of MIPS, and may open a new perspective on understanding the nature of MIPS in active systems.

cond-mat.soft↗