Trade-off between coherence and heat in a non-Markovian dephasing dynamics

TL;DR

This paper explores how quantum coherence affects thermodynamic behavior in a non-Markovian pure dephasing model, revealing a link between coherence dynamics and heat dissipation.

Contribution

It demonstrates the relationship between coherence and heat in a finite quantum system with non-Markovian effects, using a reformulated quantum thermodynamics approach.

Findings

Heat dissipation correlates with coherence decay and revivals.

Non-Markovian effects cause oscillatory coherence dynamics.

Heat and coherence are intertwined over time.

Abstract

How quantum coherence influences thermodynamic behavior remains an open question in quantum thermodynamics. Here we investigate this relation within the pure dephasing framework, where a central qubit interacts with a finite Ising-like spin environment. Although the system's internal energy remains constant, the interaction induces decoherence and gives rise to nontrivial thermodynamic features. Within the two-point measurement approach, we show that the heat dissipated into the environment matches the coherent energy contribution appearing in a reformulated first law of quantum thermodynamics. Numerical calculations reveal oscillatory coherence dynamics, with revivals associated with information backflow and non-Markovian effects, as quantified by the Breuer-Laine-Piilo measure. We find that heat and coherence exhibit intertwined temporal behavior, with enhanced heat dissipation during coherence decay and reduced heat during revivals. These results suggest a connection between coherence dynamics and thermodynamic quantities in finite, closed composite systems undergoing pure dephasing.