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Observation of photon-photon thermodynamic processes under negative optical temperature conditions

Marques Muniz AL, Wu FO, Jung PS, Khajavikhan M, Christodoulides DN, Peschel U (2023)

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Publication Type: Journal article

Publication year: 2023

Journal

Book Volume: 379

Pages Range: 1019-1023

Journal Issue: 6636

DOI: 10.1126/science.ade6523

Abstract

Statistical mechanics demands that the temperature of a system is positive provided that its internal energy has no upper bound. Yet if this condition is not met, it is possible to attain negative temperatures for which higher-order energy states are thermodynamically favored. Although negative temperatures have been reported in spin and Bose-Hubbard settings as well as in quantum fluids, the observation of thermodynamic processes in this regime has thus far remained elusive. Here, we demonstrate isentropic expansion-compression and Joule expansion for negative optical temperatures, enabled by purely nonlinear photon-photon interactions in a thermodynamic microcanonical photonic system. Our photonic approach provides a platform for exploring new all-optical thermal engines and could have ramifications in other bosonic systems beyond optics, such as cold atoms and optomechanics.

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How to cite

APA:

Marques Muniz, A.L., Wu, F.O., Jung, P.S., Khajavikhan, M., Christodoulides, D.N., & Peschel, U. (2023). Observation of photon-photon thermodynamic processes under negative optical temperature conditions. Science, 379(6636), 1019-1023. https://doi.org/10.1126/science.ade6523

MLA:

Marques Muniz, A. L., et al. "Observation of photon-photon thermodynamic processes under negative optical temperature conditions." Science 379.6636 (2023): 1019-1023.

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