Gerbier Fabrice, Fölling Simon, Widera Artur, Mandel Olaf, Bloch Immanuel
Institut für Physik, Johannes Gutenberg-Universität, 55099 Mainz, Germany.
Phys Rev Lett. 2006 Mar 10;96(9):090401. doi: 10.1103/PhysRevLett.96.090401. Epub 2006 Mar 6.
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.
通过监测超流-莫特绝缘体转变过程中自旋改变碰撞的抑制情况，对光学晶格中超冷原子的在位数涨落演化进行了实验研究。对于对应于平均填充因子接近1的低原子数，自旋改变碰撞的发生需要较大的在位数涨落。因此，自旋改变碰撞的持续抑制是数压缩态出现的直接证据。在莫特绝缘体区域，我们发现自旋改变碰撞被抑制直到一个阈值原子数，这与预期形成具有双重占据位点的莫特平台的原子数一致。
