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Q: Quantenoptik und Photonik
Q 31: Poster Fallen und Kühlung
Q 31.9: Poster
Dienstag, 14. März 2006, 16:30–18:30, Labsaal
Momentum Diffusion for Coupled Atom-Cavity Oscillators — •K Murr1, P. Maunz1, P. W. H. Pinkse1, T. Puppe1, I. Schuster1, D. Vitali2, and G. Rempe1 — 1Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Str. 1, 85748 Garching — 2Dipartimento di Fisica, Universita di Camerino, I-62032 Camerino, Italy
Strongly coupled atom-cavity systems form a cornerstone in our understanding of light-matter interaction and are promising candidates for implementation of quantum information processing protocols. However, unexpectedly large heating of the atom has been observed in these systems, as expressed by large momentum diffusion coefficients. Those coefficients have been derived before in particular cases, e.g., in Ref. [1], but questions on its origin remain.
We show that an intuitive picture can be obtained [2], in which a fluctuating dipole is coupled to a classical cavity field, and a fluctuating cavity field is coupled to a classical dipole. Actually, the equations for momentum diffusion can be cast in a simple, invariant and symmetric form, regardless of whether the atom or the cavity is excited, and regardless of the spatial structure of the involved light fields. We discuss how the quantum fluctuations of the cavity field itself are responsible for a large part of the heating. Hence, the enhanced diffusion that comes along with strong coupling must be considered as it puts constraints on applications.
[1] P. Horak et al. Phys. Rev. Lett. 79, 4974 (1997).
[2] K. Murr et al., arXiv/quant-ph 0512001 (2005).