arXiv subjects

Wei-can Yang

Publications and source records attributed to Wei-can Yang.

3 recordsLinked to original sources

arXiv2025

Non-equilibrium Dynamics and Universality of 4D Quantum Vortices and Turbulence

The study of quantum vortices provides critical insights into non-equilibrium dynamics across diverse physical systems. While previous research has focused on point-like vortices in two dimensions and line-like vortices in three dimensions, quantum vortices in four spatial dimensions are expected to take the form of extended vortex surfaces, thereby fundamentally enriching dynamics. Here, we conduct a comprehensive numerical study of 4D quantum vortices and turbulence. Using a special visualization method, we discovered the decay of topological numbers that does not exist in low dimensions, as well as the high-dimensional counterpart of the vortex reconnection process. We further explore quench dynamics across phase transitions in four dimensions and verify the applicability of the higher-dimensional Kibble-Zurek mechanism. Our simulations provide numerical evidence of 4D quantum turbulence, characterized by universal power-law behavior. These findings reveal universal principles governing topological defects in higher dimensions, offering insights for future experimental realizations using synthetic dimensions.

cond-mat.quant-gas↗

arXiv2024

Spontaneous Symmetry Breaking of Vortex Number in Binary Alternating Current Countersuperflow

In binary superfluid counterflow systems, vortex nucleation arises as a consequence of hydrodynamic instabilities when the coupling coefficient and counterflow velocity exceed the critical value. When dealing with two identical components, one might naturally anticipate that the number of vortices generated would remain equal. However, through the numerical experiments of the holographic model and the Gross-Pitaevskii equation, our investigation has unveiled a remarkable phenomenon: in Alternating Current counterflow systems, once the coupling coefficient and frequency exceed certain critical values, a surprising symmetry-breaking phenomenon occurs. This results in an asymmetry in the number of vortices in the two components. We establish that this phenomenon represents a novel continuous phase transition, which, as indicated by the phase diagram, is exclusively observable in Alternating Current counterflow. We provide an explanation for this intriguing phenomenon through soliton structures, thereby uncovering the complex and unique characteristics of quantum fluid instabilities and their rich phenomena.

cond-mat.quant-gas↗

arXiv2023

Universal defect density scaling in an oscillating dynamic phase transition

Universal scaling laws govern the density of topological defects generated while crossing an equilibrium continuous phase transition. The Kibble-Zurek mechanism (KZM) predicts the dependence on the quench time for slow quenches. By contrast, for fast quenches, the defect density scales universally with the amplitude of the quench. We show that universal scaling laws apply to dynamic phase transitions driven by an oscillating external field. The difference in the energy response of the system to a periodic potential field leads to energy absorption, spontaneous breaking of symmetry, and its restoration. We verify the associated universal scaling laws, providing evidence that the critical behavior of non-equilibrium phase transitions can be described by time-average critical exponents combined with the KZM. Our results demonstrate that the universality of critical dynamics extends beyond equilibrium criticality, facilitating the understanding of complex non-equilibrium systems.

cond-mat.stat-mech↗