An energy conserving relaxation of a 1-D Ising system

Markus Siegert, Dietrich Stauffer

Nobuyasu Ito

Tanmay Bhore, Lei Su, Ivar Martin +2 more

The Mpemba effect, where a system initially farther from equilibrium relaxes faster than one closer to equilibrium, has been extensively studied in classical systems and recently explored in quantum settings. While previous studies of the quantum Mpemba effect (QME) have largely focused on isolated systems with global symmetries, we argue that the QME is ubiquitous in generic, nonintegrable many-body systems lacking such symmetries, including U(1) charge conservation, spatial symmetries, and even energy conservation. Using paradigmatic models such as the quantum Ising model with transverse and longitudinal fields, we show that the QME can be understood through the energy density of initial states and their inverse participation ratio in the energy eigenbasis. Our findings provide a unified framework for the QME, linking it with classical thermal relaxation.

Y Achiam

A. Pawlak

The nonasymptotic critical properties of sound propagation are studied in compressible Ising system above Τ.In the present paper we analyse a model where in addition to the coupling to two order-parameter fluctuations tle sound mode couples linearly to the fluctuations of spin-energy and lattice-energy densities.Both subsystems exchange energy with the rate determined by the bare spin-lattice relaxation time: The total energy may be conserved or not.The crossover between insulator-like behaviour t -2 α a n d m e t a l -l i k e b e h a v i o u r t i t -( z v ± α ) i n u l t r a s o n i c a t t e n u a t i o n i s i n v e s t i g a t e d according to the value of ultrasonic freqnency, the reduced temperature t, bare relaxation times and various coupling constants.

Y Achiam

The relaxation of an Ising spin system which conserves the magnetization is analyzed using the time-dependent real-space renormalization group. The critical-dynamic exponent is found to be 3.74, close to the value suggested by the conventional theory.