Functional renormalization group approach to interacting bosons at zero temperature

Details Functional renormalization group approach to interacting bosons at zero temperature Functional renormalization group approach to interacting bosons at zero temperature

2010-08-26

arxiv.org/abs/1008.4521v1

Phys. Rev. A 82, 063632 (2010)

Physics

Condensed Matter

Quantum Gases

17 pages, 10 figures

Scientific paper

10.1103/PhysRevA.82.063632

We investigate the single-particle spectral density of interacting bosons within the non-perturbative functional renormalization group technique. The flow equations for a Bose gas are derived in a scheme which treats the two-particle density-density correlations exactly but neglects irreducible correlations among three and more particles. These flow equations are solved within a truncation which allows to extract the complete frequency and momentum structure of the normal and anomalous self-energies. Both the asymptotic small momentum regime, where perturbation regime fails, as well as the perturbative regime at larger momenta are well described within a single unified approach. The self-energies do not exhibit any infrared divergences, satisfy the U(1) symmetry constraints, and are in accordance with the Nepomnyashchy relation which states that the anomalous self-energy vanishes at zero momentum and zero frequency. From the self-energies we extract the single-particle spectral density of the two-dimensional Bose gas. The dispersion is found to be of the Bogoliubov form and shows the crossover from linear Goldstone modes to the quadratic behavior of quasi-free bosons. The damping of the quasiparticles is found to be in accordance with the standard Beliaev damping. We furthermore recover the exact asymptotic limit of the propagators derived by Gavoret and Nozieres and discuss the nature of the non-analyticities of the self-energies in the very small momentum regime.

Affiliated with

Also associated with

No associations

Rating

Functional renormalization group approach to interacting bosons at zero temperature does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Functional renormalization group approach to interacting bosons at zero temperature, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Functional renormalization group approach to interacting bosons at zero temperature will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-704226