Temperature in one-dimensional bosonic Mott insulators (7 pages)

Nikolay V. Prokof'ev, Carl J. Williams, Guido Pupillo

Stephen R. L. Clark

禎通 前川

Alexander Reischl, Kai Phillip Schmidt, Götz Silvester Uhrig

The Mott insulating phase of a one-dimensional bosonic gas trapped in an optical lattice is described by a Bose-Hubbard model. A continuous unitary transformation is used to map this model onto an effective model conserving the number of elementary excitations. We obtain quantitative results for the kinetics and for the spectral weights of the low-energy excitations for a broad range of parameters in the insulating phase. By these results, recent Bragg spectroscopy experiments are explained. Evidence for a significant temperature of the order of the microscopic energy scales is found.

Kai Phillip Schmidt, Alexander Reischl, Götz Silvester Uhrig

Abstract.: In this work we give a consistent picture of the thermodynamic properties of bosons in the Mott insulating phase when loaded adiabatically into one-dimensional optical lattices. We find a crucial dependence of the temperature in the optical lattice on the doping level of the Mott insulator. In the undoped case, the temperature is of the order of the large onsite Hubbard interaction. In contrast, at a finite doping level the temperature jumps almost immediately to the order of the small hopping parameter. These two situations are investigated on the one hand by considering limiting cases like the atomic limit and the case of free fermions. On the other hand, they are examined using a quasi-particle conserving continuous unitary transformation extended by an approximate thermodynamics for hardcore particles

Davide Controzzi, Fabian H. L. Eßler, Alexei M. Tsvelik