Complete screening in a one-dimensional Bose gas

Tim Langen

Marco Cominotti, F. W. J. Hekking, Anna Minguzzi

We study quantum transport of an interacting confined one-dimensional Bose gas across a barrier. A sudden shift of the confining potential induces dipolar oscillations in the cloud. We find that the dipole mode frequency strongly depends on the interaction strength between the particles, yielding information on the classical screening of the barrier and on its renormalization due to quantum fluctuations. We predict a parity effect that becomes most prominent in the strongly correlated regime.

B. Laburthe-Tolra, Kenneth M. O’Hara, J. H. Huckans +4 more

Hanoch Gutfreund, Bernardo A. Huberman

The screened interaction V(r) between two opposite charges in the classical two-dimensional Coulomb gas is discussed. This interaction appears in certain response functions of the one-dimensional fermion system, when the latter is mapped onto the two-dimensional Coulomb problem. The effect of the power-law behaviour of V(r) on these response functions, when the large momentum transfer coupling constant (g 1 ) goes to zero from below and above the g 1 =0 line, is discussed.

William D. Phillips, J. H. Huckans, B. Laburthe-Tolra +4 more

T. H. Cheung, Allan Griffin

Making use of the finite-temperature version of Beliaev's field-theoretical description of an interacting Bose gas, we sum the self-energy diagrams which correspond to the collisionless shielded potential approximation (SPA). This generalizes Bogoliubov's first-order results by replacing the bare repulsive interaction by a dynamically shielded interaction and includes the effect of the excited atoms. This theory is completely equivalent to that of Tserkovnikov if we use the ideal Bose gas approximation for the polarization function which screens the two-particle interaction. The excitation spectrum is found to have a single resonance. We do not find any convincing evidence for the additional high frequency second sound mode obtained by Tserkovnikov.