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Seminario di Dip. "Cooperative scattering of light by strongly driven atomic clouds". Relatore: Romain Bachelard

11 Ottobre, 14:30, auletta di Ottica Quantistica
Dipartimento di Fisica, Via Celoria 16, Milano

Relatore: Romain Bachelard
, Universidade Federal de Sao Cãrlos, Brazil

The scattering of light by dilute cold atomic clouds is a long-range problem by nature, as light induces an effective 1/r interaction between the atomic dipoles. Furthermore, the relative absence of decoherence allows for correlations to be preserved over long distances. Examples of long-range effects in dilute clouds include superradiance and subradiance, as well as modifications of the transition linewidth. While most previous works in dilute clouds addressed classical scattering, we study the modifications of the fluorescence spectrum due to this long-range interaction, as the atoms are strongly driven and present the so-called Mollow sidebands [1].
First, considering a large disordered cloud in front of a mirror, we show that it is possible to produce interference fringes based on the Mollow sidebands, as the radiation of the atoms and their mirror images interfere. It thus allows to extract information on the optical coherence of scatterers in disordered clouds [2].
Then, we show that the interactions of the strongly-driven atoms leads to the appearance of new peaks (higher-order Mollow sidebands) as well as a spectral asymmetry [3].
Using a truncation of the hierarchy of quantum correlations [4], the quantum dynamics of hundreds of coupled particles can thus be investigated. The reported modifications of the fluorescence spectrum thus correspond to a signature of entanglement of the atoms over large distances (i.e., many wavelengths).

[1] B. R. Mollow, Phys. Rev. 188, 1969 (1969).
[2] N. Piovella, R. Celistrino Teixeira, R. Kaiser, Ph. Courteille, and R. Bachelard, http://arxiv.org/abs/1709.04529
[3] L. Pucci, A. Roy, T. S. do Espirito Santo, R. Kaiser, M. Kastner, and R. Bachelard, Phys. Rev. A 95, 053625 (2017).
[4] L. Pucci, A. Roy, and M. Kastner, Phys. Rev. B 93, 174302 (2016).


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dott. Nicola Piovella, nicola.piovella@unimi.it

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