Momentum-resolved Raman spectroscopy of non-interacting ultracold Fermi   gas
  We report the experiment on probing the one-body spectral function in a trapped non-interacting $^{40}$K Fermi gas by means of the momentum-resolved Raman spectroscopy The experimental result is in good agreement with the expected quadratic dispersion in the non-interacting regime. Through the comparison with the radio-frequency spectrum, we found that the Raman spectrum shows some new characteristics. 
Pengjun Wang, Zhengkun Fu, Lianghui Huang, Jing Zhang
cond-mat.quant-gas