Quantum dynamics far from equilibrium: a case study in the spherical model

TL;DR

This paper explores quantum dynamics far from equilibrium using the exactly solvable quantum spherical model, focusing on non-Markovian quantum noise, quantum phase transitions, and ageing phenomena after a quantum quench.

Contribution

It provides a detailed case study of non-equilibrium quantum relaxation in the spherical model, including solutions to non-Markovian constraints and implications for quantum ageing.

Findings

Analysis of non-Markovian quantum noise effects

Insights into quantum phase transition behavior

Characterization of quantum ageing at zero temperature

Abstract

The application of quantum Langevin equations for the study of non-equilibrium relaxations is illustrated in the exactly solved quantum spherical model. Tutorial sections on the physical background of non-markovian quantum noise, the spherical model quantum phase transition, the long-time limit of the quantum Langevin equation of the spherical model and physical ageing are followed by a brief review of the solution of the non-markovian time-dependent spherical constraint and about the consequences for quantum ageing at zero temperature, after a quantum quench.