Nonequilibrium thermodynamics and optimal cooling of a dilute atomic gas
Mayer D, Schmidt F, Haupt S, Bouton Q, Adam D, Lausch T, Lutz E, Widera A (2020)
Publication Type: Journal article
Publication year: 2020
Journal
Book Volume: 2
Article Number: 023245
Journal Issue: 2
DOI: 10.1103/PhysRevResearch.2.023245
Abstract
Characterizing and optimizing thermodynamic processes far from equilibrium is a challenge. This is especially true for nanoscopic systems made of a few particles. We here theoretically and experimentally investigate the nonequilibrium dynamics of a gas of a few noninteracting cesium atoms confined in a nonharmonic optical dipole trap and exposed to degenerate Raman sideband cooling pulses. We determine the axial phase-space distribution of the atoms after each Raman cooling pulse by tracing the evolution of the gas with position-resolved fluorescence imaging. We evaluate from it the entropy production and the statistical length between each cooling step. A single Raman pulse leads to a nonequilibrium state that does not thermalize on its own, due to the absence of interparticle collisions. Thermalization may be achieved by combining free phase-space evolution and trains of cooling pulses. We minimize the entropy production to a target thermal state to specify the optimal spacing between a sequence of equally spaced pulses and achieve in this way optimal thermalization. We finally use the statistical length to verify a refined version of the second law of thermodynamics. Altogether, these findings provide a general theoretical and experimental framework to analyze and optimize far-from-equilibrium processes of few-particle systems.
Involved external institutions
Germany (DE)How to cite
APA:
Mayer, D., Schmidt, F., Haupt, S., Bouton, Q., Adam, D., Lausch, T.,... Widera, A. (2020). Nonequilibrium thermodynamics and optimal cooling of a dilute atomic gas. Physical Review Research, 2(2). https://dx.doi.org/10.1103/PhysRevResearch.2.023245
MLA:
Mayer, Daniel, et al. "Nonequilibrium thermodynamics and optimal cooling of a dilute atomic gas." Physical Review Research 2.2 (2020).
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