The quench dynamics of a dissipative quantum system: a renormalization group study

TL;DR

This paper investigates the relaxation dynamics of a dissipative quantum system after a parameter quench, using renormalization group methods to analyze non-Markovian effects in the spin-boson model.

Contribution

It introduces two complementary renormalization group approaches to study non-Markovian relaxation in a dissipative quantum system post-quench.

Findings

Non-Markovian memory significantly affects relaxation dynamics.

The methods elucidate the transition from coherent to incoherent behavior.

Results are specific to the Ohmic spin-boson model near criticality.

Abstract

We study dissipation in a small quantum system coupled to an environment held in thermodynamic equilibrium. The relaxation dynamics of a system subject to an abrupt quench in the parameters of the underlying Hamiltonian is investigated using two complementary renormalization group approaches. The methods are applied to the Ohmic spin-boson model close to the coherent-to-incoherent transition. In particular, the role of non-Markovian memory for the relaxation before and after the quench of the spin-boson coupling and the Zeeman splitting of the up and down spin is investigated.