TY - JOUR
T1 - Bragg Spectroscopy of ultracold atoms loaded in an optical lattice
JF - Physical Review A
Y1 - 2005
A1 - Ana Maria Rey
A1 - P. Blair Blakie
A1 - Guido Pupillo
A1 - Carl J. Williams
A1 - Charles W. Clark
AB - We study Bragg spectroscopy of ultra-cold atoms in one-dimensional optical lattices as a method for probing the excitation spectrum in the Mott insulator phase, in particular the one particle-hole excitation band. Within the framework of perturbation theory we obtain an analytical expression for the dynamic structure factor $S(q,\omega)$ and use it to calculate the imparted energy which has shown to be a relevant observable in recent experiments. We test the accuracy of our approximations by comparing them with numerically exact solutions of the Bose-Hubbard model in restricted cases and establish the limits of validity of our linear response analysis. Finally we show that when the system is deep in the Mott insulator regime, its response to the Bragg perturbation is temperature dependent. We suggest that this dependence might be used as a tool to probe temperatures of order of the Mott gap.
VL - 72
UR - http://arxiv.org/abs/cond-mat/0406552v2
CP - 2
J1 - Phys. Rev. A
U5 - 10.1103/PhysRevA.72.023407
ER -