Expansion dynamics of the Fulde-Ferrell-Larkin-Ovchinnikov state

Kajala, J.; Massel, Francesco; Törmä, Païvi

doi:10.1103/physreva.84.041601

Cited by 42 publications

(49 citation statements)

References 32 publications

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“…A recent experiment [12] has realized a spin-imbalanced Fermi gas in an array of 1D systems and has demonstrated that the observed density profiles are in agreement with theoretical predictions [13][14][15]. An actual experimental proof of the presence of a spatially modulated quasicondensate in this system, expected from theory [16][17][18][19][20][21], is still lacking, which has led to a large number of proposals for schemes to probe FFLO correlations [22][23][24][25][26][27]. Many of these proposals involve the presence of an optical lattice along the 1D direction, suggesting that the Fermi-Hubbard model is the appropriate model.…”

Section: Introductionmentioning

confidence: 77%

Interaction quantum quenches in the one-dimensional Fermi-Hubbard model with spin imbalance

2015

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Using the time-dependent density matrix renormalization-group method and exact diagonalization, we study the nonequilibrium dynamics of the one-dimensional Fermi-Hubbard model following a quantum quench or a ramp of the on-site interaction strength. We are particularly interested in the nonequilibrium evolution of Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) correlations, which, at finite spin polarizations and for attractive interactions, are the dominant two-body correlations in the ground state. For quenches from the noninteracting to the attractive regime, we investigate the dynamical emergence of FFLO correlations and their signatures in the pair quasi-momentum distribution function. We observe that the postquench double occupancy exhibits a maximum as the interaction strength becomes of the order of the bandwidth. Finally, we study quenches and ramps from attractive to repulsive interactions, which imprint FFLO correlations onto repulsively bound pairs. We show that a quite short ramp time is sufficient to wipe out the characteristic FFLO features in the postquench pair momentum distribution functions.

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Section: Introductionmentioning

confidence: 77%

Interaction quantum quenches in the one-dimensional Fermi-Hubbard model with spin imbalance

2015

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“…[63]. In their experiment, Papp et al studied a 85 Rb Bose-Einstein condensate, which is a strongly interacting bosonic superfluid. Traditionally, experimental studies of bosonic superfluids have been carried out on liquid helium, but a gas of Bose-condensed atoms has the advantage that the interparticle interactions can be tuned via Feshbach resonance.…”

Section: Summary Of Publication Imentioning

confidence: 99%

Elementary excitations and universal interaction in Bose-Einstein condensates at large scattering lengths

2011

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Lett. 101, 135301 (2008)]. A key feature in the experiment was the use of a Feshbach resonance, which made large values of the scattering length accessible. Due to the large values of the scattering length, existing models such as the Beliaev model could not be used to explain the observations, and therefore the experiment was a particularly interesting one to analyze. In our first approach, we constructed ad hoc potentials that fitted the observed excitation spectrum, and later we improved our approach by using T-matrix formalism to describe the Feshbach resonant system. All in all, the phenomenological model we developed fits the observed excitation spectrum and yields correct molecular Feshbach resonance state energies in certain cases.The second part of this thesis studies fermionic quantum gases. We focus on studying a gas of spin-1/2 particles confined to a spin-dependent optical lattice. The lattice geometry is such that the up-spin component is loaded in a honeycomb lattice, and the down-spin component is confined to the underlying triangular lattice. We considered attractive on-site and nearestneighbor interactions, and formulated the nearest-neighbor interaction term in such a way that it takes into account the possibility of spontaneous time-reversal symmetry breaking. Furthermore, we took into account the possibility of Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) phase, which breaks spatial symmetry. Within a mean-field approximation, we showed that the FFLO state is the ground state of the system in many instances. In addition, we found out that the system spontaneously breaks time-reversal symmetry if the nearest-neighbor interaction strength is large. Due to the time-reversal symmetry breaking, the system has topologically non-trivial phases characterized by nonzero Chern numbers. Finally, there were also cases where the time-reversal symmetry was broken in the FFLO phase, and thus we found a phase where spatial and time-reversal symmetries are simultaneously broken. Tiivistelmä Tässä väitöskirjassa käsitellään bosonisia ja fermionisia kvanttikaasuja. Työn ensimmäisessä osassa mallinnetaan eräässä Bose-kaasussa tehdyn Braggin sirontakokeen tulokset variaatiolaskentaan perustuvan monen kappaleen teorian avulla. Kokeessa sirontapituus pystyttiin säätämään suureksi Feshbach-resonanssin avulla ja tämän takia olemassa olevia malleja ei voitu käyttää tulosten selittämiseen. Tämä teki kokeesta erityisen kiinnostavan tutkimuskohteen. Ensin kehitimme joukon ad hoc -potentiaaleja, joilla sovitimme havaitun eksitaatiospektrin. Myöhemmin hyödynsimme T-matriisiformalismia Feshbach-resonanssin kuvaamisessa ja tällöin pystyimme mallintamaan myös sidottujen tilojen energioita. Yhteenvetona mallista voidaan todeta, että se mallintaa havaitun eksitaatiospektrin ja antaa oikean sidotun tilan energian joissain tapauksissa.Tämän työn toisessa osassa tutkitaan fermionisia kvanttikaasuja. Erityisesti tutkimme spinriippuvaan optiseen hilaan vangittuja spin-1/2 hiukkasia. Hilageometriassa ylös-spin komponentti liikkuu hunaja...

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“…For this reasons the imbalanced systems has been studied vigorously -both theoretically and experimentally. Theoretical studies on imbalanced systems often focus on the possibility of exploring imbalanced superconducting states in different JHEP01 (2014)136 physical systems, for example, in population-imbalanced Ultracold atomic gases [38,[40][41][42], optical lattices [43], heavy-fermionic superconductor CeCoIn 5 [44], two-dimensional organic superconductors [37,39,45,46] and quark matter core of the neutron stars [47,48]. The experimental search is a topic of vigorous research till date as it is very hard to pinpoint this state in the phase diagram.…”

Section: Condensed Matter Descriptionmentioning

confidence: 99%

Holographic entanglement entropy in imbalanced superconductors

Dutta

Modak

2014

J. High Energ. Phys.

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Abstract:We study the behavior of holographic entanglement entropy (HEE) for imbalanced holographic superconductors. We employ a numerical approach to consider the robust case of fully back-reacted gravity system. The hairy black hole solution is found by using our numerical scheme. Then it is used to compute the HEE for the superconducting case. The cases we study show that in presence of a mismatch between two chemical potentials, below the critical temperature, superconducting phase has a lower HEE in comparison to the AdS-Reissner-Nordström black hole phase. Interestingly, the effects of chemical imbalance are different in the contexts of black hole and superconducting phases. For black hole, HEE increases with increasing imbalance parameter while it behaves oppositely for the superconducting phase. The implications of these results are discussed.

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Expansion dynamics of the Fulde-Ferrell-Larkin-Ovchinnikov state

Cited by 42 publications

References 32 publications

Interaction quantum quenches in the one-dimensional Fermi-Hubbard model with spin imbalance

Interaction quantum quenches in the one-dimensional Fermi-Hubbard model with spin imbalance

Elementary excitations and universal interaction in Bose-Einstein condensates at large scattering lengths

Holographic entanglement entropy in imbalanced superconductors

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