Active Spherical Model

TL;DR

This paper extends the classical spherical model to include active matter dynamics driven by Ornstein-Uhlenbeck forces, revealing a transition from Ising to random field Ising universality as persistence time increases.

Contribution

It introduces an active spherical model with self-propulsion, demonstrating a universality shift based on the persistence time, which is a novel theoretical insight.

Findings

Model exhibits Ising universality at finite persistence time.

Model exhibits random field Ising universality as persistence time approaches infinity.

Provides a unified framework connecting active matter and critical phenomena.

Abstract

The spherical model is a popular solvable model and has been applied to describe several critical phenomena such as the ferromagnetic transition, Bose-Einstein condensation, spin-glass transition, glass transition, jamming transition, and so on. Motivated by recent developments of active matter, here we consider the spherical model driven by the Ornstein-Uhlenbeck type self-propulsion force with persistent time $\tau_p$. We show that the model exhibits the Ising universality for finite $\tau_p$. On the contrary, the model exhibits the random field Ising universality in the limit $\tau_p\to\infty$.