Fulde-Ferrell-Larkin-Ovchinnikov state in the dimensional crossover between one- and three-dimensional lattices

Kim, Dong‐Hee; Törmä, Païvi

doi:10.1103/physrevb.85.180508

Cited by 23 publications

(35 citation statements)

References 34 publications

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“…Furthermore, the magnitude of the order parameter decreases while the wavelength of the FFLO oscillation grows; this observation holds at all dimensionalities. At the low temperature limit of the phase diagrams, we find good agreement with the zero temperature results of 27 . Throughout the crossover, the lower boundary of the FFLO region in the phase diagram with respect to polarization increases with temperature.…”

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confidence: 83%

Finite-temperature stability and dimensional crossover of exotic superfluidity in lattices

2013

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We investigate exotic paired states of spin-imbalanced Fermi gases in anisotropic lattices, tuning the dimension between one and three. We calculate the finite temperature phase diagram of the system using real-space dynamical mean-field theory in combination with the quantum Monte Carlo method. We find that regardless of the intermediate dimensions examined, the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) state survives to reach about one third of the BCS critical temperature of the spin-density balanced case. We show how the gapless nature of the state found is reflected in the local spectral function. While the FFLO state is found at a wide range of polarizations at low temperatures across the dimensional crossover, with increasing temperature we find out strongly dimensionality-dependent melting characteristics of shell structures related to harmonic confinement. Moreover, we show that intermediate dimension can help to stabilize an extremely uniform finite temperature FFLO state despite the presence of harmonic confinement.

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Finite-temperature stability and dimensional crossover of exotic superfluidity in lattices

2013

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“…The same qualitative conclusion was reached in [9] using effective field theory and treating the intertube coupling as a perturbation. On the other hand, real-space DMFT studies of coupled chains [10,11] suggested rather that the FFLO state is important in the entire dimensional crossover from quasi-1D to 3D lattices. One reason for differing predictions can be that the stabilization of FFLO in lattices due to nesting [12] is stronger for coupled chains than coupled tubes.…”

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confidence: 99%

“…Moreover, there is a wide consensus that this system might demonstrate exotic forms of superfluid pairing when subjected to, e.g., a spin population imbalance. The prospects of realizing such forms of conventional and exotic superfluidity in systems of intermediate dimensionality have been discussed broadly in the literature [6][7][8][9][10][11]. However, the role of nonlocal quantum fluctuations remains to a large degree an open question in these systems even in the case of the conventional BCS pairing.…”

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Nonlocal Quantum Fluctuations and Fermionic Superfluidity in the Imbalanced Attractive Hubbard Model

et al. 2014

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“…Correspondingly, mean-field calculations [30,31] and realspace dynamical mean-field theory (DMFT) for fermions in anisotropic optical lattices find a stable and extended spatially modulated superfluid [32][33][34]. However, such approximations are particularly questionable in 2D.…”

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Fulde-Ferrell-Larkin-Ovchinnikov pairing as leading instability on the square lattice

Gukelberger¹,

Lienert²,

Kozik³

et al. 2016

Phys. Rev. B

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We study attractively interacting spin-1 2 fermions on the square lattice subject to a spin population imbalance. Using unbiased diagrammatic Monte Carlo simulations we find an extended region in the parameter space where the Fermi liquid is unstable towards formation of Cooper pairs with nonzero center-of-mass momentum, known as the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) state. In contrast to earlier mean-field and quasi-classical studies we provide quantitative and well-controlled predictions on the existence and location of the relevant Fermi-liquid instabilities. The highest temperature where the FFLO instability can be observed is about half of the superfluid transition temperature in the unpolarized system. PACS numbers: 71.10. Hf,37.10.Jk,74.20.Mn Fifty years after the initial prediction by Fulde, Ferrell, Larkin, and Ovchinnikov (FFLO) [1,2], superconducting phases with spontaneously broken translational invariance are still at the center of interest in such diverse fields as solid state physics, cold atomic gases, nuclear physics, and dense quark matter in neutron stars [3][4][5][6][7]. While the underlying mechanism is generic enough to apply to any partially polarized Fermi system, it has proven surprisingly difficult to unambiguously observe such phases in nature. Recently, however, experimental evidence has been mounting for their existence in heavy fermion compounds [8][9][10] and layered organic materials [11][12][13][14][15]. On the other hand, experiments with ultracold atoms, which are among the cleanest imbalanced Fermi systems without the need for a magnetic field, so far failed to demonstrate inhomogeneous superfluidity [16,17] -although there is some evidence for such a phase in one dimension (1D) [18] -possibly due to small extent of the parameter region where an FFLO phase may exist in three dimensions (3D) and difficulties in reaching sufficiently low temperatures [5].On the theoretical side, results on the existence and nature of FFLO phases based on well-controlled microscopic theories are scarce, with the exception of 1D systems, where exact analytical and numerical studies are possible [19][20][21][22][23][24][25], and where finite-momentum pairing is a generic feature of the spin-imbalanced phase diagram. In higher dimensions, most studies are based on effective field theories in the neighborhood of critical points or resort to quasi-classical or mean-field approximations. For 3D Fermi gases, many features of the mean-field phase diagram [26] have been corroborated by fixed-node diffusion quantum Monte Carlo calculations [27]; whether the FFLO phase does exist in a small sliver of the phase diagram, as predicted by the mean-field theory, is however still subject to debate.The FFLO state is expected [3,4] to occupy a larger parameter region in two dimensions (2D), and lattice effects may further increase its stability [28,29]. Correspondingly, mean-field calculations [30,31] and realspace dynamical mean-field theory (DMFT) for fermions in anisotropic optical lattices find a st...

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Fulde-Ferrell-Larkin-Ovchinnikov state in the dimensional crossover between one- and three-dimensional lattices

Cited by 23 publications

References 34 publications

Finite-temperature stability and dimensional crossover of exotic superfluidity in lattices

Finite-temperature stability and dimensional crossover of exotic superfluidity in lattices

Nonlocal Quantum Fluctuations and Fermionic Superfluidity in the Imbalanced Attractive Hubbard Model

Fulde-Ferrell-Larkin-Ovchinnikov pairing as leading instability on the square lattice

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