Probing number squeezing of ultracold atoms across the superfluid-Mott insulator transition.
The evolution of on-site number fluctuations of ultracold atoms in optical lattices is experimentally investigated by monitoring the suppression of spin-changing collisions across the superfluid-Mott insulator transition. For low atom numbers, corresponding to an average filling factor close to unity, large on-site number fluctuations are necessary for spin-changing collisions to occur. The continuous suppression of spin-changing collisions is thus direct evidence for the emergence of number-squeezed states. In the Mott insulator regime, we find that spin-changing collisions are suppressed until a threshold atom number, consistent with the number where a Mott plateau with doubly occupied sites is expected to form.
Gerbier
Fabrice
F
Institut für Physik, Johannes Gutenberg-Universität, 55099 Mainz, Germany. fabrice.gerbier@lkb.ens.fr
Fölling
Simon
S
Widera
Artur
A
Mandel
Olaf
O
Bloch
Immanuel
I