Quantum noise spectroscopy of dynamical critical phenomena

TL;DR

This paper introduces a noise spectroscopy method that detects phase transitions, extracts critical exponents, and identifies universality classes, especially useful for studying quantum critical phenomena in magnetic materials.

Contribution

It presents a novel noise spectroscopy approach that characterizes criticality and universality classes in phase transitions, including quantum and classical cases.

Findings

Noise spectroscopy can diagnose phase transitions.

Critical exponents can be extracted from decoherence profiles.

The method distinguishes classical from quantum criticality.

Abstract

The transition between distinct phases of matter is characterized by the nature of fluctuations near the critical point. We demonstrate that noise spectroscopy can not only diagnose the presence of a phase transition, but can also determine fundamental properties of its criticality. In particular, by analyzing a scaling collapse of the decoherence profile, one can directly extract the critical exponents of the transition and identify its universality class. Our approach naturally captures the presence of conservation laws and distinguishes between classical and quantum phase transitions. In the context of quantum magnetism, our proposal complements existing techniques and provides a novel toolset optimized for interrogating two-dimensional magnetic materials.