Critical Dynamics in Holographic First-Order Phase Transition

TL;DR

This paper investigates the universal critical dynamics during first-order phase transitions using holographic models, revealing how seed nuclei and shock wave collisions influence the transition and the role of temperature.

Contribution

It introduces a novel shock wave collision mechanism to study critical phenomena and analyzes the universality and temperature dependence of critical nuclei in holographic phase transitions.

Findings

Critical phenomena are universal and shape-independent.

A new shock wave collision mechanism can induce critical states.

Higher temperature increases the critical nucleus depth, hindering phase separation.

Abstract

We study the critical phenomena of the dynamical transition from a metastable state to a stable state in the model of first-order phase transition via two different triggering mechanisms. Three universal stages during the fully nonlinear evolution are extracted. On the one side, by perturbing the scalar source, an isolated seed nucleus is injected into an initial homogeneous state in the supercooled region. For critical parameters of the seed nucleus, the real-time dynamics reveal that the system will converge to a critically unstable state. For supercritical parameters, the system exhibits a phase separation, while for subcritical parameters falls back to homogeneous. The shape independence of the seed nucleus is also investigated, which implies that the critical phenomena are universal. On the other side, we propose a novel mechanism to render the critical phenomena via a collision of two gravitational shock waves on the dual geometries. Specifying a collision velocity, the initial system can be also attracted to a critically unstable state. Aside from these dynamical constructions, we also quantitatively analyze the critical nucleus preventing the system from reaching the final phase separation. We find the depth of the critical nucleus increases almost linearly with the temperature, which implies that the hotter the supercooled state is, the harder for it to trigger phase separation.