Imbalanced Feshbach-resonant Fermi gases

Radzihovsky, Leo; Sheehy, Daniel E.

doi:10.1088/0034-4885/73/7/076501

Cited by 200 publications

(226 citation statements)

References 194 publications

(593 reference statements)

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“…However, when the difference between Ω FF and Ω LO is plotted, see Fig.1(c), it is clear that the LO state has a lower energy and thus forms the ground state of the system. In conclusion, we find that also in a lattice the LO and not the FF state forms the ground state of the system, which is in agreement with previous work comparing FF and LO in a homogeneous system [16,20,24,43].…”

Section: A Comparing the Fulde-ferrell And Larkin-ovchinnikov Statessupporting

confidence: 93%

Larkin-Ovchinnikov phases in two-dimensional square lattices

Baarsma

Törmä

2016

Journal of Modern Optics

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We consider a two-component gas of fermions in optical lattices in the presence of a population imbalance within a mean-field theory. We study phase transitions from a normal gas of unpaired fermions to a superfluid phase of Bose-condensed Cooper pairs. The possibility of Cooper pairs with a nonzero center-of-mass momentum is included, which corresponds to a so-called Fulde-FerrelLarkin-Ovchinnikov (FFLO) state. We find that for population imbalanced systems such states can form the ground state. The FF and LO state are compared and it is shown that actually the LO state is energetically more favorable. We complete the mean-field phase diagram for the LO phase and show that it is qualitatively in excellent agreement with recent diagrammatic Monte Carlo calculations. Subsequently, we calculate the atomic density modulations in the LO phase.

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Section: A Comparing the Fulde-ferrell And Larkin-ovchinnikov Statessupporting

confidence: 93%

Larkin-Ovchinnikov phases in two-dimensional square lattices

Baarsma

Törmä

2016

Journal of Modern Optics

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“…(5) and (6), respectively. On the other hand, the same equations withβ = 0 apply as well to a different physical setting, viz., a degenerate Fermi gas with spin 1/2, in which φ ↓ and φ ↑ represent two spin components, coupled by the MW magnetic field [6,38]. The following analysis is chiefly dealing with the zerodetuning (symmetric) system, η = 0.…”

Section: Figmentioning

confidence: 99%

Stable giant vortex annuli in microwave-coupled atomic condensates

2016

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Stable self-trapped vortex annuli (VAs) with large values of topological charge S (giant VAs) are not only a subject of fundamental interest, but are also sought for various applications, such as quantum information processing and storage. However, in conventional atomic Bose-Einstein condensates (BECs) VAs with S > 1 are unstable. Here, we demonstrate that robust self-trapped fundamental solitons (with S = 0) and bright VAs (with the stability checked up to S = 5), can be created in the free space by means of the local-field effect (the feedback of the BEC on the propagation of electromagnetic waves) in a condensate of two-level atoms coupled by a microwave (MW) field, as well as in a gas of MW-coupled fermions with spin 1/2. The fundamental solitons and VAs remain stable in the presence of an arbitrarily strong repulsive contact interaction (in that case, the solitons are constructed analytically by means of the Thomas-Fermi approximation). Under the action of the attractive contact interaction with strength β, which, by itself, would lead to collapse, the fundamental solitons and VAs exist and are stable, respectively, at β < β max (S) and β < β st (S), with β st (S = 0) = β max (S = 0) and β st (S ≥ 1) < β max (S ≥ 1). Accurate analytical approximations are found for both β st and β max , with β st (S) growing linearly with S. Thus, higher-order VAs are more robust than their lower-order couterparts, on the contrary to what is known in other systems that may support stable self-trapped vortices. Conditions for the experimental realizations of the VAs are discussed.

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“…An particular example that attracts intense interests is the ground state of a two-component, spin-population imbalanced Fermi gas of 6 Li or 40 K atoms [3,4]. In the strongly interacting regime, observation of new exotic superfluid states in the imbalanced systems may be anticipated, such as the spatially inhomogeneous FuldeFerrell-Larkin-Ovchinnikov state [5][6][7][8][9][10][11][12].…”

Section: Introductionmentioning

confidence: 99%

Virial expansion for a strongly correlated Fermi gas with imbalanced spin populations

Liu

2010

Phys. Rev. A

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Quantum virial expansion provides an ideal tool to investigate the high-temperature properties of a strongly correlated Fermi gas. Here, we construct the virial expansion in the presence of spin population imbalance. Up to the third order, we calculate the high-temperature free energy of a unitary Fermi gas as a function of spin imbalance, with infinitely large, attractive or repulsive interactions. In the latter repulsive case, we show that there is no itinerant ferromagnetism when quantum virial expansion is applicable. We therefore estimate an upper bound for the ferromagnetic transition temperature Tc. For a harmonically trapped Fermi gas at unitarity, we find that (Tc)uppper < TF , where TF is the Fermi temperature at the center of the trap. Our result for the high-temperature equations of state may confront future high-precision thermodynamic measurements.

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Imbalanced Feshbach-resonant Fermi gases

Cited by 200 publications

References 194 publications

Larkin-Ovchinnikov phases in two-dimensional square lattices

Larkin-Ovchinnikov phases in two-dimensional square lattices

Stable giant vortex annuli in microwave-coupled atomic condensates

Virial expansion for a strongly correlated Fermi gas with imbalanced spin populations

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