Fluctuation-Induced Heat Release from Temperature-Quenched Nuclear Spins near a Quantum Critical Point

TL;DR

This study demonstrates that nuclear spins in a quantum antiferromagnet release heat when annealed by quantum fluctuations near a quantum critical point, revealing the dynamics of critical fluctuations through calorimetric measurements.

Contribution

It provides experimental evidence of fluctuation-induced heat release from nuclear spins near a QCP, serving as a new probe of quantum critical dynamics.

Findings

Detectable heat release from nuclear spins near QCP

Nuclear spins annealed by quantum fluctuations

Quantum critical region characterized by heat signatures

Abstract

At a quantum critical point (QCP) -- a zero-temperature singularity in which a line of continuous phase transition terminates -- quantum fluctuations diverge in space and time, leading to exotic phenomena that can be observed at non-zero temperatures. Using a quantum antiferromagnet, we present calorimetric evidence that nuclear spins frozen in a high-temperature metastable state by temperature quenching are annealed by quantum fluctuations near the QCP. This phenomenon, with readily detectable heat release from the nuclear spins as they are annealed, serves as an excellent marker of a quantum critical region around the QCP and provides a probe of the dynamics of the divergent quantum fluctuations.