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Pairing patterns in one-dimensional spin- and mass-imbalanced Fermi gases

by Lukas Rammelmüller, Joaquín E. Drut, Jens Braun

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Submission summary

Authors (as registered SciPost users): Jens Braun · Lukas Rammelmüller
Submission information
Preprint Link:  (pdf)
Date accepted: 2020-07-10
Date submitted: 2020-07-03 02:00
Submitted by: Rammelmüller, Lukas
Submitted to: SciPost Physics
Ontological classification
Academic field: Physics
  • Atomic, Molecular and Optical Physics - Theory
  • Condensed Matter Physics - Computational
Approaches: Theoretical, Computational


We study spin- and mass-imbalanced mixtures of spin-$\tfrac{1}{2}$ fermions interacting via an attractive contact potential in one spatial dimension. Specifically, we address the influence of unequal particle masses on the pair formation by means of the complex Langevin method. By computing the pair-correlation function and the associated pair-momentum distribution we find that inhomogeneous pairing is present for all studied spin polarizations and mass imbalances. To further characterize the pairing behavior, we analyze the density-density correlations in momentum space, the so-called shot noise, which is experimentally accessible through time-of-flight imaging. At finite spin polarization, the latter is known to show distinct maxima at momentum configurations associated with the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) instability. Besides those maxima, we find that additional features emerge in the noise correlations when mass imbalance is increased, revealing the stability of FFLO-type correlations against mass imbalance and furnishing an experimentally accessible signature to probe this type of pairing.

List of changes

- fixed some inconsitencies w.r.t. the definition of the center-of-mass momentum / total momentum
- a colorbar was added to Fig. 4, Fig. 6 and Fig. 7
- a paragraph was added in Sect. 5, to further clarify the nature of our findings
- a footnote was added in Sect. 4, to provide a (rough) translation to known parameter values in the literature

Published as SciPost Phys. 9, 014 (2020)

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