Regensburg 2010 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 37: MLT: Poster Session

TT 37.31: Poster

Donnerstag, 25. März 2010, 14:00–18:00, Poster A

Spectral properties of coupled cavity arrays in one dimension — •Michael Knap, Enrico Arrigoni, and Wolfgang von der Linden — Institute of Theoretical and Computational Physics, Graz University of Technology, 8010 Graz, Austria

The experimental progress in controlling quantum optical and atomic systems, which has been achieved over the last few years, prompted ideas for new realizations of strongly-correlated many body systems, such as light-matter systems [1]. These systems consist of photons confined in optical cavities, which interact strongly with atomic-like structures. Similarly to the Bose-Hubbard model the light-matter systems exhibit a quantum phase transition from Mott to superfluid. Yet the physics of the latter is far richer as two types of particles are present.

We use the variational cluster approach (VCA) [2] to study the physics of light-matter models. This method allows to treat systems of large size and at zero temperature. In particular we evaluate the spectral functions of both photons as well as atomic-excitations [3]. Based on this information we are able to introduce polariton quasiparticles as appropriate, wave vector and filling dependent linear combinations of photons and atomic-like particles. Spectral properties are evaluated for the polariton particles and the weights of their constituents are analyzed. In addition we discuss improvements of VCA, more specifically the Q-matrix formalism, to deal with bosonic excitations.

[1] M. Hartmann, et al., Laser & Photonics Review 2, 527 (2008).

[2] M. Potthoff, et al., Phys. Rev. Lett. 91, 206402 (2003).

[3] M. Knap, E. Arrigoni, and W. von der Linden, arXiv:0912.4459.