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Title: Parity effect in a mesoscopic Fermi gas

Authors:
; ;
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
1256989
Grant/Contract Number:
BES DESC0001911
Resource Type:
Journal Article: Publisher's Accepted Manuscript
Journal Name:
Physical Review A
Additional Journal Information:
Journal Volume: 93; Journal Issue: 6; Related Information: CHORUS Timestamp: 2016-06-13 19:56:29; Journal ID: ISSN 2469-9926
Publisher:
American Physical Society
Country of Publication:
United States
Language:
English

Citation Formats

Hofmann, Johannes, Lobos, Alejandro M., and Galitski, Victor. Parity effect in a mesoscopic Fermi gas. United States: N. p., 2016. Web. doi:10.1103/PhysRevA.93.061602.
Hofmann, Johannes, Lobos, Alejandro M., & Galitski, Victor. Parity effect in a mesoscopic Fermi gas. United States. doi:10.1103/PhysRevA.93.061602.
Hofmann, Johannes, Lobos, Alejandro M., and Galitski, Victor. 2016. "Parity effect in a mesoscopic Fermi gas". United States. doi:10.1103/PhysRevA.93.061602.
@article{osti_1256989,
title = {Parity effect in a mesoscopic Fermi gas},
author = {Hofmann, Johannes and Lobos, Alejandro M. and Galitski, Victor},
abstractNote = {},
doi = {10.1103/PhysRevA.93.061602},
journal = {Physical Review A},
number = 6,
volume = 93,
place = {United States},
year = 2016,
month = 6
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1103/PhysRevA.93.061602

Citation Metrics:
Cited by: 1work
Citation information provided by
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  • We study the dynamics of time-of-flight expansion of an atomic Fermi system with a finite number of particles N after it is released from a harmonic trapping potential. We consider two different initial states: the Fermi sea state and the paired state. In the former case, we derive exact and simple analytic expressions for the dynamics of the particle density and density-density correlation functions, taking into account the level quantization and possible anisotropy of the trap. To describe the paired state, we use the projection of the grand-canonical BCS wave function onto the subspace with a fixed number of particles,more » and obtain analytic expressions for the density and its correlators in the leading order with respect to the ratio of the trap frequency and the superconducting gap (the ratio is assumed small). We discuss several dynamic features, such as the time evolution of the peak due to pair correlations, which may be used to distinguish between the Fermi sea and the paired state.« less
  • We have studied the distinctive features of the Fulde-Ferrel-Larkin-Ovchinnikov (FFLO) instability and phase transitions in two-dimensional (2D) mesoscopic superconductors placed in magnetic field of arbitrary orientation and rotating superfluid Fermi gases with imbalanced state populations. Using a generalized version of the phenomenological Ginzburg-Landau theory we have shown that the FFLO states are strongly modified by the effect of the trapping potential confining the condensate. The phenomenon of the inhomogeneous state formation is determined by the interplay of three length scales: (i) length scale of the FFLO instability; (ii) 2D system size; (iii) length scale associated with the orbital effect causedmore » either by the Fermi condensate rotation or magnetic field component applied perpendicular to the superconducting disk. We have studied this interplay and resulting quantum oscillation effects in both superconducting and superfluid finite-size systems with FFLO instability and described the hallmarks of the FFLO phenomenon in a restricted geometry. The finite size of the system is shown to affect strongly the conditions of the observability of switching between the states with different vorticities.« less
  • During the last decade, experiments all over the world started to test the superconducting state of matter using a newly developed mesoscopic tunable system: trapped ultra-cold atomic gases. Theorists and experimentalists hand-in-hand are now able to advance our understanding of the superconducting state by asking new questions that probe further into the physical mechanisms underlying the phenomenon and the door is open to the exploration of exotic unconventional superconducting states. In particular, a series of experiments on systems of trapped cold atomic gases were aimed at studying the effects of polarization on superconducting pairing. Two different experimental groups encountered surprisingmore » qualitative and quantitative discrepancies which seemed to be a function of the confining geometry and the cooling protocol. Our numerical studies demonstrate a tendency towards metastability and suggest an explanation for the observed discrepancy. From our calculations, the most likely solution which is consistent with the experiments supports a state strikingly similar to the so called FFLO state (after Ferrell, Fulde, Larkin and Ovchinnikov), which had been theorized long ago but eluded detection so far. Moreover, the three-dimensional scenario described above is reminiscent of predictions for one-dimensional systems of dilute polarized attractive gases and another set of ultra-cold-atom experiments incorporates optical lattices to study this reduced-dimensionality setting. The measurements are in quantitative agreement with theoretical calculations (using a wide array of numerical and analytic techniques) in which a partially polarized phase is found to be the one-dimensional analogue of the FFLO state. Moreover, exploring the dimensional-crossover regime, our latest findings indicate that the mesoscopic nature of these quasi-one-dimensional systems favors the appearance of a new type of Mott phase transition involving an emergent pair-superfluid of equal-spin fermions.« less
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