Landau damping in dilute Bose gases

R.J. Ragan, W.J. Mullin, E.B. Wiita

Robert Seiringer

S. Giorgini

Damping in a dilute Bose gas is investigated using a mean-field approximation which describes the coupled oscillations of condensate and noncondensate atoms in the collisionless regime. Explicit results for both Landau and Beliaev damping rates are given for nonuniform gases. In the case of uniform systems, we obtain results for the damping of phonons both at zero and finite temperature. The isothermal compressibility of a uniform gas is also discussed.

Ryan Wilson, Stefan S. Natu

Seyed Mostafa Moniri, H. Yavari, Elnaz Darsheshdar

Ming-Chiang Chung, Aranya B. Bhattacherjee

Damping in two-dimensional (2D) and 3D dilute gases is investigated using both the hydrodynamical approach and the Hartree–Fock–Bogoliubov (HFB) approximation. We found that both methods are good for Beliaev damping at zero temperatures and Landau damping at very low temperatures. However, at high temperatures, the hydrodynamical approach overestimates the Landau damping and HFB gives a precise asymptotic behavior. This result shows that the comparison of the theoretical calculation using the hydrodynamical approach and the experimental data for high temperatures by Vincent Liu (1997 Phys. Rev. Lett. 79 4056) is not valid. For 2D systems, we show that the Beliaev damping rate is proportional to k 3 and the Landau damping rate is proportional to T 2 for low temperatures and to T for high temperatures. We also show that in 2D the hydrodynamical approach gives the same result for zero temperature and for low temperature as HFB, but overestimates the Landau damping for high temperatures.