Pseudomode treatment of strong-coupling quantum thermodynamics

Abstract

The treatment of quantum thermodynamic systems beyond weak coupling is of increasing relevance, yet extremely challenging. The evaluation of thermodynamic quantities in strong-coupling regimes requires a nonperturbative knowledge of the bath dynamics, which in turn relies on heavy numerical simulations. To tame these difficulties, considering thermal bosonic baths linearly coupled to the open system, we derive expressions for heat, work, and average system-bath interaction energy that only involve the autocorrelation function of the bath and two-time expectation values of system operators. We then exploit the pseudomode approach, which replaces the physical continuous bosonic bath with a small finite number of damped, possibly interacting, modes, to numerically evaluate these relevant thermodynamic quantities. We show in particular that this method allows for an efficient numerical evaluation of thermodynamic quantities in terms of one-time expectation values of the open system and the pseudomodes. We apply this framework to the investigation of two paradigmatic situations. In the first instance, we study the entropy production for a two-level system coupled to an ohmic bath, simulated via interacting pseudomodes, allowing for the presence of time-dependent driving. Secondly, we consider a quantum thermal machine composed of a two-level system interacting with two thermal baths at different temperatures, showing that an appropriate sinusoidal modulation of the coupling with the cold bath only is enough to obtain work extraction.

23 pages, 5 figures

References in corpus (11)

• Quantum trajectories and open many-body quantum systems
• Non-perturbative treatment of non-Markovian dynamics of open quantum systems
• Quantum thermodynamic devices: from theoretical proposals to experimental reality
• Performance of a quantum heat engine at strong reservoir coupling
• Non-Markovian Quantum Trajectories Versus Master Equations: Finite Temperature Heat Bath
• Non-Markov Enhancement of Maximum Power for Quantum Thermal Machines
• Fundamental limits for cooling of linear quantum refrigerators
• Open systems with error bounds: spin boson model with spectral density variations
• Hybrid quantum thermal machines with dynamical couplings
• Dynamics of a strongly coupled quantum heat engine -- computing bath observables from the hierarchy of pure states
• General theory for thermal and nonthermal quantum linear engines

Cited by in corpus (5)

• Open quantum systems with particle and bath driven by time-dependent fields
• Input-Output Hierarchical Equations Of Motion
• Local energy assignment for two interacting quantum thermal reservoirs
• Subtleties in the pseudomodes formalism
• Purified pseudomode model for nonlinear system-bath interactions