Regensburg 2013 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 19: Quantum Liquids, Miscellaneous 2

TT 19.5: Vortrag

Montag, 11. März 2013, 16:00–16:15, H21

Exotic Ising dynamics in a Bose-Hubbard model — •Luis Seabra and Frank Pollmann — Max-Planck-Institut fur Physik komplexer Systeme, 01187 Dresden, Germany

We explore the dynamical properties of a one-dimensional Bose-Hubbard model, where two different bosonic species interact via Feshbach resonance. We focus on the region in the phase diagram which is described by an effective, low-energy ferromagnetic Ising model in both transverse and longitudinal fields. In this regime, we numerically calculate the Ising dynamical structure factor of the Bose-Hubbard model using the Time-Evolving Block Decimation method. In the ferromagnet phase, we observe both the continuum of excitations and the bound states for different values of the longitudinal field. Near the Ising critical point, we observe the celebrated E₈ mass spectrum in the excited states. We also discuss possible measurements which could be used to detect these excitations in an optical lattice experiment.