Autonomous rotor heat engine

Abstract

The triumph of heat engines is their ability to convert the disordered energy of thermal sources into useful mechanical motion. In recent years, much effort has been devoted to generalizing thermodynamic notions to the quantum regime, partly motivated by the promise of surpassing classical heat engines. Here, we instead adopt a bottom-up approach: we propose a realistic autonomous heat engine that can serve as a test bed for quantum effects in the context of thermodynamics. Our model draws inspiration from actual piston engines and is built from closed-system Hamiltonians and weak bath coupling terms. We analytically derive the performance of the engine in the classical regime via a set of nonlinear Langevin equations. In the quantum case, we perform numerical simulations of the master equation. Finally, we perform a dynamic and thermodynamic analysis of the engine's behavior for several parameter regimes in both the classical and quantum case and find that the latter exhibits a consistently lower efficiency due to additional noise.

Work production of quantum rotor engines

“…The second part in (3) reflects the systematic effect and the backaction noise that comes directly from thermalization. It is only present if the Lindblad dissipators representing the thermal contact to the baths explicitly depend on ĵ ; the incoherent energy exchange between the working fluid and the environment then constitutes an effective nonselective measurement channel for the piston position that results in momentum diffusion [7].…”

“…An exemplary time evolution of the rates at which work accumulates in the rotor is plotted in figure 2(a), comparing the intrinsic mechanical power expressions of section 2.1 with the time derivative of the ergotropy (7). With no backaction present, the power (4) associated to the intrinsic force equals the rate of change…”

Quantum current in dissipative systems

“…Moreover, unlike heat to work conversion, which is fairly well understood both classically [11,12] and quantumly [13,14], motion generation solely utilizing thermal disequilibrium has mainly remained in the focus of classical thermodynamics and transport [11,12,[15][16][17][18]. Only a handful of models have been studied in the quantum regime: except for several works [19][20][21][22][23] studying the (angular) momentum in continuous-variable thermal rotors, to our knowledge, only [24] studies persistent current generation in a fully quantum model, albeit in the limit of the moving part being isolated from the environment.…”

Deep-subwavelength lithography via graphene plasmons

“…Future work will extend this idea to structures with more cylinders, include an autonomous engine design [34,35], and explore the applications of work correlation.…”