title: Observation of collective atomic recoil motion in a degenerate fermion gas.
abstract: We demonstrate collective atomic recoil motion with a dilute, ultracold, degenerate fermion gas in a single spin state. By utilizing an adiabatically decompressed magnetic trap with an aspect ratio different from that of the initial trap, a momentum-squeezed fermion cloud is achieved. With a single pump pulse of the proper polarization, we observe, for the first time, multiple wave-mixing processes that result in distinct collective atomic recoil motion modes in a degenerate fermion cloud. Contrary to the case with Bose condensates, no pump-laser detuning asymmetry is present.
authors.affiliation: The State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Opto-Electronics, Shanxi University, Taiyuan 030006, People's Republic of China.
authors.forename: Pengjun
authors.initials: P
authors.lastname: Wang
authors.forename: L
authors.initials: L
authors.lastname: Deng
authors.forename: E W
authors.initials: EW
authors.lastname: Hagley
authors.forename: Zhengkun
authors.initials: Z
authors.lastname: Fu
authors.forename: Shijie
authors.initials: S
authors.lastname: Chai
authors.forename: Jing
authors.initials: J
authors.lastname: Zhang