2014/02/28 by Nathan R. Bernier, Emanuele G. Dalla Torre, Eugene Demler · 1 citation
Physics and Astronomy · #cond-mat.quant-gas
paper · pdf · doi:10.1103/physrevlett.113.065303
published as Phys. Rev. Lett. 113, 065303 (2014) · 5 pages, 3 figures, 1 table
arxiv created 2014/03/05 · arxiv updated 2014/08/07
We consider the dynamics of a Bose-Einstein condensate with two internal states, coupled through a coherent drive. We focus on a specific quench protocol, in which the sign of the coupling field is suddenly changed. At a mean-field level, the system is transferred from a minimum to a maximum of the coupling energy and can remain dynamically stable, in spite of the development of negative- frequency modes. In the presence of a non-zero detuning between the two states, the "charge" and "spin" modes couple, giving rise to an unstable avoided crossing. This phenomenon is generic to systems with two dispersing modes away from equilibrium and constitutes an example of class-Io non-equilibrium pattern formation in quantum systems.