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arXiv · 1806.06906

Phase space density limitation in laser cooling without spontaneous emission

Thierry Chanelière·Daniel Comparat·Hans Lignier
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Abstract

We study the possibility to enhance the phase space density of non-interacting particles submitted to a classical laser field without spontaneous emission. We clearly state that, when no spontaneous emission is present, a quantum description of the atomic motion is more reliable than semi-classical description which can lead to large errors especially if no care is taken to smooth structures smaller than the Heisenberg uncertainty principle. Whatever the definition of position - momentum phase space density, its gain is severely bounded especially when started from a thermal sample. More precisely, the maximum phase space density, can only be improved by a factor M for M-level atoms. This bound comes from a transfer between the external and internal degrees of freedom. To circumvent this limit, one can use non-coherent light fields, informational feedback cooling schemes, involve collectives states between fields and atoms, or allow a single spontaneous emission even

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Thierry Chanelière, Daniel Comparat, Hans Lignier. 2018-06-18. Phase space density limitation in laser cooling without spontaneous emission. https://doi.org/10.1103/physreva.98.063432

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