Commensurate-incommensurate transition of cold atoms in an optical lattice.
An atomic gas subject to a commensurate periodic potential generated by an optical lattice undergoes a superfluid-Mott insulator transition. Confining a strongly interacting gas to one dimension generates an instability where an arbitrary weak potential is sufficient to pin the atoms into the Mott state; here, we derive the corresponding phase diagram. The commensurate pinned state may be detected via its finite excitation gap and the Bragg peaks in the static structure factor.
Büchler
H P
HP
Theoretische Physik, ETH-Hönggerberg, CH-8093 Zürich, Switzerland.
Blatter
G
G
Zwerger
W
W