July 29 2016

New article: Localization transition in the presence of cavity backaction

Our article Localization transition in the presence of cavity backaction has been published in the most recent volume of Physical Review A.

Localization transition in the presence of cavity backaction

Katharina Rojan, Rebecca Kraus, Thomás Fogarty, Hessam Habibian, Anna Minguzzi, and Giovanna Morigi
Phys. Rev. A. 94, 013839

We study the localization transition of an atom confined by an external optical lattice in a high-finesse cavity. The atom-cavity coupling yields an effective secondary lattice potential, whose wavelength is incommensurate with the periodicity of the optical lattice. The cavity lattice can induce localization of the atomic wave function analogously to the Aubry-André localization transition. Starting from the master equation for the cavity and the atom we perform a mapping of the system dynamics to a Hubbard Hamiltonian, which can be reduced to the Harper's Hamiltonian in appropriate limits. We evaluate the phase diagram for the atom's ground state and show that the transition between extended and localized wave function is controlled by the strength of the cavity nonlinearity, which determines the size of the localized region and the behavior of the Lyapunov exponent. The Lyapunov exponent, in particular, exhibits resonancelike behavior in correspondence with the optomechanical resonances. Finally we discuss the experimental feasibility of these predictions.



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