# Quantum critical states and phase transitions in the presence of non equilibrium noise

## TL;DR

This paper explores how non-equilibrium 1/f noise influences quantum critical points, revealing that such noise can preserve critical correlations and allow quantum phase transitions to occur outside equilibrium.

## Contribution

It demonstrates that 1/f noise can sustain quantum critical correlations and enable quantum phase transitions under non-equilibrium conditions, a novel insight in quantum many-body physics.

## Key findings

- 1/f noise preserves quantum critical correlations
- Quantum phase transitions can occur out of equilibrium
- External noise influences quantum states in unexpected ways

## Abstract

Quantum critical points are characterized by scale invariant correlations and correspondingly long ranged entanglement. As such, they present fascinating examples of quantum states of matter, the study of which has been an important theme in modern physics. Nevertheless very little is known about the fate of quantum criticality under non equilibrium conditions. In this paper we investigate the effect of external noise sources on quantum critical points. It is natural to expect that noise will have a similar effect to finite temperature, destroying the subtle correlations underlying the quantum critical behavior. Surprisingly we find that in many interesting situations the ubiquitous 1/f noise preserves the critical correlations. The emergent states show intriguing interplay of intrinsic quantum critical and external noise driven fluctuations. We demonstrate this general phenomenon with specific examples in solid state and ultracold atomic systems. Moreover our approach shows that genuine quantum phase transitions can exist even under non equilibrium conditions.