Solid State and Optics Seminar

Wednesday, March 1, 2006

1:00 p.m.

107 Mason Lab

"Bosons in a 2D Optical Lattice: an experimental study"

Dr. Ian Spielman,
N.I.S.T.

Abstract

Ultra-cold atoms confined to optical lattices are a unique condensed matter system -- which in the most simple case faithfully represents the Bose-Hubbard Hamiltonian. This system supports a superfluid to Mott-insulator transition in 2 and 3 dimensions; in this talk I will focus on the 2D case.

Bose-condensed rubidium atoms are loaded into a 3D optical lattice with an average occupancy of one atom per-site. An ensemble of 2D lattice systems are realized when one direction of the 3D lattice is much deeper than the remaining two. These 2D systems exhibit a superfluid-insulator transition as the lattice depth (in the remaining 2 directions) is increased. I present new measurements that show that the conventional signature of long-range order, namely diffraction, disappears continuously as the Mott state develops, likewise the coherence-length continuously decreases. We additionally probe this transition via correlations in atom shot noise, which further identify the coherence properties of the system.

Host: David DeMille