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arXiv · 2407.11858

Condensation of vanishing photon emission rates in random atomic clouds

Viviana Viggiano·Romain Bachelard·Fabio Deelan Cunden·Paolo Facchi·Robin Kaiser·Saverio Pascazio·Francesco V. Pepe·Antonello Scardicchio
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Abstract

In the collective photon emission from atomic clouds both the atomic transition frequency and the decay rate are modified compared to a single isolated atom, leading to the effects of superradiance and subradiance. In this article, we analyse the properties of the Euclidean random matrix associated to the radiative dynamics of a cold atomic cloud, previously investigated in the contexts of photon localization and Dicke super- and subradiance. We present evidence of a new type of phase transition, surprisingly controlled by the cooperativeness parameter, rather than the spatial density or the diagonal disorder. The numerical results corroborate the occurrence of such a phase transition at a critical value of the cooperativeness parameter, above which the lower edge of the spectrum vanishes exhibiting a macroscopic accumulation of eigenvalues. Independent evaluations based on the two phenomena provide the same value of the critical cooperativeness parameter.

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Viviana Viggiano, Romain Bachelard, Fabio Deelan Cunden, Paolo Facchi, Robin Kaiser, Saverio Pascazio, Francesco V. Pepe, Antonello Scardicchio. 2024-07-16. Condensation of vanishing photon emission rates in random atomic clouds. https://doi.org/10.1103/v4vy-wn4p

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