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Title: Core structure of two-dimensional Fermi gas vortices in the BEC-BCS crossover region

Abstract

We report T = 0 diffusion Monte Carlo results for the ground-state and vortex excitation of unpolarized spin-1/2 fermions in a two-dimensional disk. We investigate how vortex core structure properties behave over the BEC-BCS crossover. We calculate the vortex excitation energy, density pro les, and vortex core properties related to the current. We nd a density suppression at the vortex core on the BCS side of the crossover and a depleted core on the BEC limit. Size-effect dependencies in the disk geometry were carefully studied.

Authors:
 [1];  [2];  [1]
  1. Arizona State Univ., Mesa, AZ (United States)
  2. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
USDOE Office of Science (SC). Nuclear Physics (NP) (SC-26); USDOE
OSTI Identifier:
1406210
Alternate Identifier(s):
OSTI ID: 1355068
Report Number(s):
LA-UR-17-21896
Journal ID: ISSN 2469-9926; PLRAAN; TRN: US1703256
Grant/Contract Number:
AC52-06NA25396; AC02-05CH11231
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Physical Review A
Additional Journal Information:
Journal Volume: 95; Journal Issue: 5; Journal ID: ISSN 2469-9926
Publisher:
American Physical Society (APS)
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; Atomic and Nuclear Physics

Citation Formats

Madeira, Lucas, Gandolfi, Stefano, and Schmidt, Kevin E. Core structure of two-dimensional Fermi gas vortices in the BEC-BCS crossover region. United States: N. p., 2017. Web. doi:10.1103/PhysRevA.95.053603.
Madeira, Lucas, Gandolfi, Stefano, & Schmidt, Kevin E. Core structure of two-dimensional Fermi gas vortices in the BEC-BCS crossover region. United States. doi:10.1103/PhysRevA.95.053603.
Madeira, Lucas, Gandolfi, Stefano, and Schmidt, Kevin E. Tue . "Core structure of two-dimensional Fermi gas vortices in the BEC-BCS crossover region". United States. doi:10.1103/PhysRevA.95.053603. https://www.osti.gov/servlets/purl/1406210.
@article{osti_1406210,
title = {Core structure of two-dimensional Fermi gas vortices in the BEC-BCS crossover region},
author = {Madeira, Lucas and Gandolfi, Stefano and Schmidt, Kevin E.},
abstractNote = {We report T = 0 diffusion Monte Carlo results for the ground-state and vortex excitation of unpolarized spin-1/2 fermions in a two-dimensional disk. We investigate how vortex core structure properties behave over the BEC-BCS crossover. We calculate the vortex excitation energy, density pro les, and vortex core properties related to the current. We nd a density suppression at the vortex core on the BCS side of the crossover and a depleted core on the BEC limit. Size-effect dependencies in the disk geometry were carefully studied.},
doi = {10.1103/PhysRevA.95.053603},
journal = {Physical Review A},
number = 5,
volume = 95,
place = {United States},
year = {Tue May 02 00:00:00 EDT 2017},
month = {Tue May 02 00:00:00 EDT 2017}
}

Journal Article:
Free Publicly Available Full Text
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Cited by: 2works
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  • Cited by 2
  • We investigate the crossover from Bardeen-Cooper-Schrieffer (BCS) superfluidity to Bose-Einstein condensation (BEC) in a two-dimensional Fermi gas at T=0 using the fixed-node diffusion Monte Carlo method. We calculate the equation of state and the gap parameter as a function of the interaction strength, observing large deviations compared to mean-field predictions. In the BEC regime our results show the important role of dimer-dimer and atom-dimer interaction effects that are completely neglected in the mean-field picture. Results on Tan's contact parameter associated with short-range physics are also reported along the BCS-BEC crossover.
  • Cited by 28
  • We present a theoretical study of the ground state of the BCS-BEC crossover in dilute two-dimensional Fermi gases. While the mean-field theory provides a simple and analytical equation of state, the pressure is equal to that of a noninteracting Fermi gas in the entire BCS-BEC crossover, which is not consistent with the features of a weakly interacting Bose condensate in the BEC limit and a weakly interacting Fermi liquid in the BCS limit. The inadequacy of the two-dimensional mean-field theory indicates that the quantum fluctuations are much more pronounced than those in three dimensions. In this work, we show thatmore » the inclusion of the Gaussian quantum fluctuations naturally recovers the above features in both the BEC and the BCS limits. In the BEC limit, the missing logarithmic dependence on the boson chemical potential is recovered by the quantum fluctuations. Near the quantum phase transition from the vacuum to the BEC phase, we compare our equation of state with the known grand canonical equation of state of two-dimensional Bose gases and determine the ratio of the composite boson scattering length a B to the fermion scattering length a 2D. We find a B ≃ 0.56a 2D, in good agreement with the exact four-body calculation. As a result, we compare our equation of state in the BCS-BEC crossover with recent results from the quantum Monte Carlo simulations and the experimental measurements and find good agreements.« less