Advanced search
1 file | 639.39 KB

Quasiparticle properties of an impurity in a Fermi gas

(2013) PHYSICAL REVIEW B. 87(11).
Author
Organization
Project
HPC-UGent: the central High Performance Computing infrastructure of Ghent University
Abstract
We report a study of a spin-down impurity strongly coupled to a spin-up Fermi sea (a so-called Fermi polaron) with the diagrammatic Monte Carlo (DiagMC) technique. Conditions of zero temperature and three dimensions are considered for an ultracold atomic gas with resonant interactions in the zero-range limit. A Feynman diagrammatic series is developed for the one-body and two-body propagators providing information about the polaron and molecule channel, respectively. The DiagMC technique allows us to reach diagram orders that are high enough for extrapolation to infinite order. The robustness of the extracted results is examined by checking various resummation techniques and by running the simulations with various choices for the propagators and vertex functions. It turns out that dressing the lines in the diagrams as much as possible is not always the optimal choice. We also identify classes of dominant diagrams for the one-body and two-body self-energy in the region of strong interaction. These dominant diagrams turn out to be the leading processes of the strong-coupling limit. The quasiparticle energies and Z factor are obtained as a function of the interaction strength. We find that the DiagMC results for the molecule and polaron properties are very similar to those obtained with a variational ansatz. Surprisingly, this variational ansatz gives very good predictions for the quasiparticle residue even when this residue is significantly less than 1.

Downloads

  • PhysRevB.87.115133.pdf
    • full text
    • |
    • open access
    • |
    • PDF
    • |
    • 639.39 KB

Citation

Please use this url to cite or link to this publication:

Chicago
Vlietinck, Jonas, Jan Ryckebusch, and Kris Van Houcke. 2013. “Quasiparticle Properties of an Impurity in a Fermi Gas.” Physical Review B 87 (11).
APA
Vlietinck, J., Ryckebusch, J., & Van Houcke, K. (2013). Quasiparticle properties of an impurity in a Fermi gas. PHYSICAL REVIEW B, 87(11).
Vancouver
1.
Vlietinck J, Ryckebusch J, Van Houcke K. Quasiparticle properties of an impurity in a Fermi gas. PHYSICAL REVIEW B. 2013;87(11).
MLA
Vlietinck, Jonas, Jan Ryckebusch, and Kris Van Houcke. “Quasiparticle Properties of an Impurity in a Fermi Gas.” PHYSICAL REVIEW B 87.11 (2013): n. pag. Print.
@article{3174675,
  abstract     = {We report a study of a spin-down impurity strongly coupled to a spin-up Fermi sea (a so-called Fermi polaron) with the diagrammatic Monte Carlo (DiagMC) technique. Conditions of zero temperature and three dimensions are considered for an ultracold atomic gas with resonant interactions in the zero-range limit. A Feynman diagrammatic series is developed for the one-body and two-body propagators providing information about the polaron and molecule channel, respectively. The DiagMC technique allows us to reach diagram orders that are high enough for extrapolation to infinite order. The robustness of the extracted results is examined by checking various resummation techniques and by running the simulations with various choices for the propagators and vertex functions. It turns out that dressing the lines in the diagrams as much as possible is not always the optimal choice. We also identify classes of dominant diagrams for the one-body and two-body self-energy in the region of strong interaction. These dominant diagrams turn out to be the leading processes of the strong-coupling limit. The quasiparticle energies and Z factor are obtained as a function of the interaction strength. We find that the DiagMC results for the molecule and polaron properties are very similar to those obtained with a variational ansatz. Surprisingly, this variational ansatz gives very good predictions for the quasiparticle residue even when this residue is significantly less than 1.},
  articleno    = {115133},
  author       = {Vlietinck, Jonas and Ryckebusch, Jan and Van Houcke, Kris},
  issn         = {1098-0121},
  journal      = {PHYSICAL REVIEW B},
  language     = {eng},
  number       = {11},
  pages        = {11},
  title        = {Quasiparticle properties of an impurity in a Fermi gas},
  url          = {http://dx.doi.org/10.1103/PhysRevB.87.115133},
  volume       = {87},
  year         = {2013},
}

Altmetric
View in Altmetric
Web of Science
Times cited: