Universal cooling dynamics towards a quantum critical point

Abstract

We investigate the loss of adiabaticity when cooling a many-body quantum system from an initial thermal state towards a quantum critical point. The excitation density, which quantifies the degree of adiabaticity of the dynamics, is found to obey scaling laws in the cooling velocity as well as in the initial and final temperatures of the cooling protocol. The scaling laws are universal, governed by the critical exponents of the quantum phase transition. The validity of these statements is shown analytically for a Kitaev quantum wire coupled to Markovian baths, and subsequently argued to be valid under rather general conditions. Our results establish that quantum critical properties can be probed dynamically at finite temperature, without even varying the control parameter of the quantum phase transitions.Comment: 5+4 pages, 2+2 figures; companion paper to "Long-range Kitaev chain in a thermal bath: Analytic techniques for time-dependent systems and environments" by the same authors and submitted on the same da