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Phases of a 2D Bose Gas in an Optical Lattice



Karina K. Jimenez Garcia, Yu-Ju Lin, James V. Porto, Ian B. Spielman


Ultra-cold atoms in optical lattices realize essential models in condensed matter physics. Like with most experiments with ultra-cold atoms, our Rubidium-87 Bose Einstein condensate is confined in a harmonic trapping potential that persists even when loaded into an optical lattice. Here we realize the 2D Bose-Hubbard Hamiltonian and focus on the effects of the trapping term, not present in bulk condensed matter systems. By measuring condensate fraction we identify the transition from superfluid to insulator as a function of atom density and lattice depth. Our results are in excellent agreement with the Quantum Monte Carlo universal state diagram suitable for the trapped systems introduced by Rigol et. al. (Phys. Rev. A 79, 053605 (2009)).
Physical Review Letters


atomic physics, Bose-Einstein condensate (BEC), Bose-Hubbard model, Mott insulator, optical lattices, phase diagram, quantum gases


Jimenez, K. , Lin, Y. , Porto, J. and Spielman, I. (2010), Phases of a 2D Bose Gas in an Optical Lattice, Physical Review Letters, [online], (Accessed April 19, 2024)
Created September 9, 2010, Updated November 10, 2018