Non-equilibrium dynamics of a system with Quantum Frustration

TL;DR

This paper investigates the non-equilibrium dynamics of a two-level quantum system coupled to two baths, revealing symmetry-protected energy splitting and faster decoherence in non-equilibrium states due to quantum frustration.

Contribution

It introduces a flow equation approach to analyze both equilibrium and non-equilibrium behaviors of a frustrated two-level system with non-commuting bath couplings, highlighting novel dynamical features.

Findings

Symmetric coupling protects the energy splitting in equilibrium.

A critical asymmetry angle determines localized versus delocalized phases.

Decoherence occurs faster with two baths than with a single bath in non-equilibrium states.

Abstract

Using flow equations, equilibrium and non-equilibrium dynamics of a two-level system are investigated, which couples via non-commuting components to two independent oscillator baths. In equilibrium the two-level energy splitting is protected when the TLS is coupled symmetrically to both bath. A critical asymmetry angle separates the localized from the delocalized phase. On the other hand, real-time decoherence of a non-equilibrium initial state is for a generic initial state faster for a coupling to two baths than for a single bath.