Nonequilibrium quantum phase transition in itinerant electron systems

TL;DR

This paper investigates how applying a voltage bias affects the ferromagnetic phase transition in a one-dimensional itinerant electron system, revealing a shift from equilibrium to mean-field critical behavior under nonequilibrium conditions.

Contribution

It demonstrates that voltage bias changes the universality class of the ferromagnetic transition, providing new insights into nonequilibrium quantum phase transitions.

Findings

Voltage bias induces a nonequilibrium steady state with current.

The universality class shifts from uniaxial ferroelectric to mean-field.

The transition exhibits mean-field behavior near the critical point.

Abstract

We study the effect of the voltage bias on the ferromagnetic phase transition in a one-dimensional itinerant electron system. The applied voltage drives the system into a nonequilibrium steady state with a non-zero electric current. The bias changes the universality class of the second order ferromagnetic transition. While the equilibrium transition belongs to the universality class of the uniaxial ferroelectric, we find the mean-field behavior near the nonequilibrium critical point.