Observation of heat scaling across a first-order quantum phase transition in a spinor condensate

TL;DR

This study experimentally demonstrates a power-law scaling of heat during a first-order quantum phase transition in a spinor condensate, providing new insights into non-equilibrium thermodynamics.

Contribution

It provides the first experimental observation of heat scaling in a first-order quantum phase transition, confirming theoretical predictions.

Findings

Heat exhibits power-law scaling across a first-order QPT.

Experimental results agree with numerical simulations.

Heat measurement was achieved via atom number probing.

Abstract

Heat generated as a result of the breakdown of an adiabatic process is one of the central concepts of thermodynamics. In isolated systems, the heat can be defined as an energy increase due to transitions between distinct energy levels. Across a second-order quantum phase transition (QPT), the heat is predicted theoretically to exhibit a power-law scaling, but it is a significant challenge for an experimental observation. In addition, it remains elusive whether a power-law scaling of heat can exist for a first-order QPT. Here we experimentally observe a power-law scaling of heat in a spinor condensate when a system is linearly driven from a polar phase to an antiferromagnetic phase across a first-order QPT. We experimentally evaluate the heat generated during two non-equilibrium processes by probing the atom number on a hyperfine energy level. The experimentally measured scaling exponents agree well with our numerical simulation results. Our work therefore opens a new avenue to experimentally and theoretically exploring the properties of heat in non-equilibrium dynamics.