Dresden 2011 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
TT: Fachverband Tiefe Temperaturen
TT 37: MLT: Quantum Liquids, Bose-Einstein Condensates, Ultra-cold Atoms, ...
TT 37.4: Vortrag
Mittwoch, 16. März 2011, 14:45–15:00, HSZ 105
Ginzburg-Landau theory for the Jaynes-Cummings-Hubbard model — •Christian Nietner1, Axel Pelster2, Gernot Schaller1, and Tobias Brandes1 — 1ITP, TU Berlin, Hardenbergstr. 36, 10623 Berlin, Germany — 2FB Physik, Uni Duisburg-Essen, Lotharstr. 1, 47048 Duisburg, Germany
We develop a Ginzburg-Landau theory for the Jaynes-Cummings-Hubbard model, which describes the thermodynamics of photons evolving in an infinite lattice of cavities each filled with a two-level atom. Following Ref. [1], we calculate the effective action in first order of the hopping term. With this we reproduce at first the finite-temperature mean-field result of Refs. [2,3] for the quantum phase boundary between a Mott-insulating and a superfluid phase of polaritons. Subsequently, we investigate the excitation spectra in both the Mott phase and the superfluid phase. We find that our results for the energy gap and the effective masses of the particle and hole excitations in the superfluid phase are in good quantitative agreement with Ref. [4]. We determine the sound velocity of polaritons as a function of the detuning between the cavity mode and the two-level system. Finally, we outline how to obtain finite-size corrections to these results.
[1] B. Bradlyn, F. E. A. dos Santos, and A. Pelster, Phys. Rev. A 79, 013615 (2009).
[2] J. Koch and K. L. Hur, Phys. Rev. A 80, 023811 (2009).
[3] S. Schmidt and G. Blatter, Phys. Rev. Lett. 103, 086403 (2009).
[4] S. Schmidt and G. Blatter, Phys. Rev. Lett. 104, 216402 (2010).