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Q: Fachverband Quantenoptik und Photonik

Q 56: Poster IV

Q 56.12: Poster

Donnerstag, 5. März 2009, 16:30–19:00, VMP 9 Poster

Thermodynamically unstable phases in the Bose-Fermi-Hubbard model — •Alexander Mering and Michael Fleischhauer — Fachbereich Physik, Technische Universität Kaiserslautern, D-67663 Kaiserslautern

The Bose-Fermi-Hubbard model in the case of ultrafast fermions can be described by an effective bosonic Hubbard Hamiltonian including fermion-induced long-range density-density interactions. The resulting model displays a variety of different phases. Beside the well known charge-density wave phase (CDW), for which the amplitude of the CDW can be determined analytically through a selfconsistent treatment of the effective boson Hamiltonian, thermodynamically unstable phases arise. In the corresponding parameter regimes spatially separated Mott-insulator (MI) and CDW regions coexist. Starting from the derivation of the effective bosonic Hamiltonian and the analytic study of the phase diagramm we discuss the emergence of this unstable phase. The analytic results are complemented by numerical simulations using density-matrix-renormalization-group methods.