Persistence of coherent quantum dynamics at strong dissipation

TL;DR

This paper demonstrates that in a two-state quantum system coupled to a sub-Ohmic reservoir, coherent quantum dynamics persist even under strong dissipation, challenging traditional expectations of incoherent decay.

Contribution

It provides numerically exact evidence that coherence can survive strong dissipation in certain quantum systems, highlighting the persistence of quantum effects.

Findings

Coherent dynamics do not necessarily decay into incoherence under strong dissipation.

System-reservoir entanglement persists in non-equilibrium states.

Quantum coherence remains in regimes previously thought to be classical.

Abstract

The quantum dynamics of a two state system coupled to a bosonic reservoir with sub-Ohmic spectral density is investigated for strong friction. Numerically exact path integral Monte Carlo methods reveal that in contrast to conventional expectations, coherent dynamics never turns into incoherent decay for a broad class of spectral distributions. Coherences associated with substantial system-reservoir entanglement exist in non-equilibrium even when strong dissipation makes the thermodynamic state of the system to behave essentially classical. This may be of relevance for current experiments with nanoscale devices and bio-molecular aggregates.