arXiv subjects

Jinghua Fu

Publications and source records attributed to Jinghua Fu.

8 recordsLinked to original sources

arXiv2026

Model Study of Eigen-Microstate Signatures of Criticality in Relativistic Heavy-Ion Collisions

We present a comprehensive model study of the eigen-microstate approach (EMA) for identifying critical fluctuations in relativistic heavy-ion collisions. Using UrQMD and two stochastic baseline models, we demonstrate that EMA is insensitive to conventional short-range correlations and effectively filters out non-critical backgrounds. Critical fluctuations embedded via event-level or particle-level replacement with CMC events generate characteristic cluster-like eigen-microstate patterns and enhanced leading eigenvalues, with event-level criticality producing stronger responses. The eigen microstates exhibit the same pattern across different scales, demonstrating that the fractal nature of critical fluctuations is captured by the eigen microstates. Finite-size scaling of eigenvalue ratios exhibits fixed-point behavior, confirming the largest eigenvalue as an effective order-parameter-like quantity. These results demonstrate that EMA offers a robust and background-independent method for critical-point searches in the RHIC Beam Energy Scan and future heavy-ion experiments.

nucl-th↗

arXiv2025

Relaxation dynamics and the free energy near the phase boundary of the 3D kinetic Ising model

We investigate relaxation dynamics along the entire first-order phase transition line by analyzing the time evolution of the free energy landscape in the three-dimensional kinetic Ising model. Near the critical temperature $T_{\rm c}$, the free energy structure is consistent with predictions from Landau-Ginzburg theory. At temperatures far below $T_{\rm c}$, however, fine structures in pre-equilibrium configurations trap random initial states, causing a pronounced delay in equilibration - an effect we identify as ultra-slow relaxation. This phenomenon is characterized by a self-divergence of the relative variance of equilibration times, which we propose as a previously unrecognized hallmark of first-order phase transitions.

cond-mat.stat-mech↗

arXiv2024

Relaxation behavior near the first-order phase transition line

Using the Metropolis algorithm, we simulate the relaxation process of the three-dimensional kinetic Ising model. Starting from a random initial configuration, we first present the average equilibration time across the entire phase boundary. It is observed that the average equilibration time increases significantly as the temperature decreases far from the critical temperature $T_{\rm c}$. The average equilibration time along the first-order phase transition (1st-PT) line exhibits an ultra-slow relaxation. We also investigate the dynamic scaling behavior with system sizes, and find that dynamic scaling holds not only near $T_{\rm c}$, but also at $T\ll T_{\rm c}$. The dynamic exponent at $T\ll T_{\rm c}$ is larger than that near $T_{\rm c}$. Additionally, we analyze the dynamic scaling of the average autocorrelation time and find that it depends on system size only near $T_{\rm c}$, while it becomes size-independent both above and below $T_{\rm c}$. The extremely slow relaxation dynamics observed near the 1st-PT is attributed to the complex structure of the free energy.

cond-mat.stat-mech↗

arXiv2023

The nonequilibrium evolution near the phase boundary

Using the single-spin flipping dynamics, we study the nonequilibrium evolution near the entire phase boundary of the 3D Ising model, and find that the average of relaxation time (RT) near the first-order phase transition line (1st-PTL) is significantly larger than that near the critical point (CP). As the system size increases, the average of RT near the 1st-PTL increases at a higher power compared to that near the CP. We further show that RT near the 1st-PTL is not only non-self-averaging, but actually self-diverging: relative variance of RT increases with system size. The presence of coexisting and metastable states results in a substantial increase in randomness near the 1st-PTL, and therefore makes the equilibrium more difficult to achieve.

cond-mat.stat-mech↗

arXiv2022

Investigations into the characteristics and influences of nonequilibrium evolution

In order to estimate qualitatively the influence of nonequilibrium evolution in relativistic heavy ion collisions, we use the three dimensional Ising model with Metropolis algorithm to study the evolution from nonequilibrium to equilibrium on the phase boundary. The evolution of order parameter approaches its equilibrium value exponentially, the same as that given by Langevin equation. The average relaxation time is defined which is demonstrated to well represent the relaxation time in dynamical equations. It is shown that the average relaxation time at critical temperature diverges as the zth power of system size. The third and the fourth cumulants of order parameter during the nonequilibrium evolution could be either positive or negative, depending on the observation time, consistent with dynamical models at T > Tc. It is found that the nonequilibrium evolution at T > Tc lasts very short, and the influence is weaker than that at T < Tc. Those qualitative features are instructive to determine experimentally the critical point and the phase boundary of QCD.

cond-mat.stat-mech↗

arXiv2003

Extracting Event Dynamics from Event-by-Event Analysis

The problem of eliminating the statistical fluctuations and extracting the event dynamics from event-by-event analysis is discussed. New moments $G_p$ (for continuous distribution), and $G_{q,p}$ (for anomalous distribution) are proposed, which are experimentally measurable and can eliminate the Poissonian type statistical fluctuations to recover the dynamical moments $C_p$ and $C_{q,p}$. In this way, the dynamical distribution of the event-averaged transverse momentum $\bar{\pt}$ can be extracted, and the anomalous scaling of dynamical distribution, if exists, can be recovered, through event-by-event analysis of experimental data.

hep-ph↗

arXiv2000

Anisotropy of Dynamical Fluctuations as a Probe for Soft and Hard Processes in High Energy Collisions

It is shown using Lund Monte Carlo that, unlike the average properties of the hadronic system inside jets, the anisotropy of dynamical fluctuations in these systems changes abruptly with the variation of the cut parameter $y_cut$. A transition point exists, where the dynamical fluctuations in the hadronic system inside jet behave like those in soft hadronic collisions. Thus the anisotropy property of the dynamical fluctuations can serve as a probe for the soft and hard processes in high energy collisions.

hep-ph↗

arXiv1999

On the Intermittency and Chaos in High Energy Collisions

It is shown that an event sample from the Monte Carlo simulation of a random cascading αmodel with fixed dynamical fluctuation strength is intermittent but not chaotic, while the variance of dynamical fluctuation strength in different events will result in both the intermittency and the chaotic behavior. This shows that fractality and chaoticity are two connected but different features of non-linear dynamics in high energy collisions.

hep-ph↗