超冷6Li费米气体的密度涨落和亚泊松分布

本文实验测量了无相互作用下6Li超冷费米原子气体密度分布的空间噪声涨落.在量子简并条件下,研究了理想费米气体的空间原子噪声涨落和量子简并度之间的关系,在实验上研究了泡利排斥对量子简并费米气体密度涨落的有效抑制,实现了低温费米量子气体的亚泊松分布测量.本文发展的原子密度噪声测量方法和测量结果在强相关多体系统的温度测量和观测不可压缩量子相的相变方面具有较大的应用前景.

Density fluctuations and sub-Poisson distribution in the ultracold Fermi gas of 6Li

In this paper,we study the spatial noise fluctuations of the density distribution of non-interacting 6Li ultracold Fermi gases.For ideal ultracold Fermi gases,the Fermi-Dirac statistics governs its quantum distribution.The suppression of density fluctuations at low temperature,due to Pauli exclusion principle,is observed in a large cloud of fermions.To clearly reveal the density noise fluctuations of the ideal Fermi gases,other noises,such as the background noise,imaging laser noise,CCD photon counting noise,are greatly suppressed.The noise fluctuation shows a sub-Poissonian statistics in excess of 10,000 atoms per spin state.The dependence of the spatial atom noise fluctuation on the quantum degeneracy is also investigated by changing the temperature of the degenerated Fermi gases.The Fermi gases with lower temperature exhibit larger suppression of the noise fluctuations.The results may have great applications in measuring the temperature of strongly correlated many-body physics and observing the phase transition of incompressible quantum phases.