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Title: Finite-size and particle-number effects in an ultracold Fermi gas at unitarity

Abstract

We investigate an ultracold Fermi gas at unitarity confined in a periodic box V=L{sup 3} using renormalization group techniques. Within this approach we can quantitatively assess the long-range bosonic order parameter fluctuations, which dominate finite-size effects. We determine the finite-size and particle-number dependence of universal quantities, such as the Bertsch parameter and the fermion gap. Moreover, we analyze how these universal observables respond to the variation of an external pairing source. Our results indicate that the Bertsch parameter saturates rather quickly to its value in the thermodynamic limit as a function of increasing box size. On the other hand, we observe that the fermion gap shows a significantly stronger dependence on the box size, in particular for small values of the pairing source. Our results may contribute to a better understanding of finite-size and particle-number effects present in Monte Carlo simulations of ultracold Fermi gases.

Authors:
 [1];  [2];  [3]
  1. Theoretisch-Physikalisches Institut, Friedrich-Schiller-Universitaet Jena, Max-Wien-Platz 1, D-07743 Jena (Germany)
  2. Institut fuer Theoretische Physik, Universitaet Innsbruck, A-6020 Innsbruck (Austria)
  3. Institut fuer Theoretische Festkoerperphysik, RWTH Aachen, Otto-Blumenthalstrasse, D-52074 Aachen (Germany)
Publication Date:
OSTI Identifier:
22095667
Resource Type:
Journal Article
Journal Name:
Physical Review. A
Additional Journal Information:
Journal Volume: 84; Journal Issue: 6; Other Information: (c) 2011 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 1050-2947
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 74 ATOMIC AND MOLECULAR PHYSICS; COMPUTERIZED SIMULATION; FERMI GAS; FERMIONS; FLUCTUATIONS; INTERACTION RANGE; MONTE CARLO METHOD; ORDER PARAMETERS; PERIODICITY; RENORMALIZATION; UNITARITY

Citation Formats

Braun, Jens, Diehl, Sebastian, Institute for Quantum Optics and Quantum Information of the Austrian Academy of Sciences, A-6020 Innsbruck, and Scherer, Michael M. Finite-size and particle-number effects in an ultracold Fermi gas at unitarity. United States: N. p., 2011. Web. doi:10.1103/PHYSREVA.84.063616.
Braun, Jens, Diehl, Sebastian, Institute for Quantum Optics and Quantum Information of the Austrian Academy of Sciences, A-6020 Innsbruck, & Scherer, Michael M. Finite-size and particle-number effects in an ultracold Fermi gas at unitarity. United States. https://doi.org/10.1103/PHYSREVA.84.063616
Braun, Jens, Diehl, Sebastian, Institute for Quantum Optics and Quantum Information of the Austrian Academy of Sciences, A-6020 Innsbruck, and Scherer, Michael M. Thu . "Finite-size and particle-number effects in an ultracold Fermi gas at unitarity". United States. https://doi.org/10.1103/PHYSREVA.84.063616.
@article{osti_22095667,
title = {Finite-size and particle-number effects in an ultracold Fermi gas at unitarity},
author = {Braun, Jens and Diehl, Sebastian and Institute for Quantum Optics and Quantum Information of the Austrian Academy of Sciences, A-6020 Innsbruck and Scherer, Michael M.},
abstractNote = {We investigate an ultracold Fermi gas at unitarity confined in a periodic box V=L{sup 3} using renormalization group techniques. Within this approach we can quantitatively assess the long-range bosonic order parameter fluctuations, which dominate finite-size effects. We determine the finite-size and particle-number dependence of universal quantities, such as the Bertsch parameter and the fermion gap. Moreover, we analyze how these universal observables respond to the variation of an external pairing source. Our results indicate that the Bertsch parameter saturates rather quickly to its value in the thermodynamic limit as a function of increasing box size. On the other hand, we observe that the fermion gap shows a significantly stronger dependence on the box size, in particular for small values of the pairing source. Our results may contribute to a better understanding of finite-size and particle-number effects present in Monte Carlo simulations of ultracold Fermi gases.},
doi = {10.1103/PHYSREVA.84.063616},
url = {https://www.osti.gov/biblio/22095667}, journal = {Physical Review. A},
issn = {1050-2947},
number = 6,
volume = 84,
place = {United States},
year = {2011},
month = {12}
}