In-medium bound states of two bosonic impurities in a one-dimensional Fermi gas

Huber, David; Hammer, H.-W.; Volosniev, A. G.

doi:10.1103/physrevresearch.1.033177

Cited by 25 publications

(19 citation statements)

References 74 publications

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“…We choose another approach. We estimate the induced impurity-impurity interaction using the Born-Oppenheimer approximation [50][51][52] (see Refs. [53][54][55][56][57] for related studies in three spatial dimensions), i.e., for m → ∞.…”

Section: A Bose Gas With Two Impurity Atomsmentioning

confidence: 99%

Impurities in a one-dimensional Bose gas: the flow equation approach

et al. 2021

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A few years ago, flow equations were introduced as a technique for calculating the ground-state energies of cold Bose gases with and without impurities[1,2]. In this paper, we extend this approach to compute observables other than the energy. As an example, we calculate the densities, and phase fluctuations of one-dimensional Bose gases with one and two impurities. For a single mobile impurity, we use flow equations to validate the mean-field results obtained upon the Lee-Low-Pines transformation. We show that the mean-field approximation is accurate for all values of the boson-impurity interaction strength as long as the phase coherence length is much larger than the healing length of the condensate. For two static impurities, we calculate impurity-impurity interactions induced by the Bose gas. We find that leading order perturbation theory fails when boson-impurity interactions are stronger than boson-boson interactions. The mean-field approximation reproduces the flow equation results for all values of the boson-impurity interaction strength as long as boson-boson interactions are weak.

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Section: A Bose Gas With Two Impurity Atomsmentioning

confidence: 99%

Impurities in a one-dimensional Bose gas: the flow equation approach

et al. 2021

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“…Previous theoretical works on interacting Bose-Fermi mixtures have uncovered a variety of different ground-state phases 5-21 . One-dimensional Bose-Fermi mixtures, which show peculiar properties owing to the enhanced role of quantum fluctuations 22 , have also received a sustained interest [23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41] .…”

Section: Introductionmentioning

confidence: 99%

Induced pairing of fermionic impurities in a one-dimensional strongly correlated Bose gas

Pasek¹,

Orso²

2019

Phys. Rev. B

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We investigate numerically the problem of few (one, two) noninteracting spin−1/2 fermions in a shallow harmonic trap coupled via contact repulsive interactions to a uniform one-dimensional bath of lattice bosons, described by the Bose-Hubbard model. Through extensive density-matrix renormalization group calculations, we extract the binding energy and the effective mass of quasiparticles, including dressed impurities (polarons) and their two-body bound states (bipolarons), emerging from the effective non-local Casimir interaction between the impurities. We show that the mixture exhibits rather different pairing behaviors depending on the singlet vs. triplet spin state configurations of the two fermions. For opposite spin states, bipolarons are found for any finite value of the impurity-bath coupling. In particular, in the strong coupling regime their binding energy reduces to that of a single polaron, provided the boson-boson repulsion is not too weak. For equal spin states, we show that bipolarons emerge only beyond a critical strength of the Bose-Fermi interaction and their effective mass grows rapidly approaching the strong coupling regime.

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“…One interesting application of the complex Langevin method is to study the transition from degenerate Fermi-polaron regime to classical Boltzmann-gas regime of a unitary spinimbalanced Fermi gas which is found to be a sharp transition by a cold-atom experiment using 6 Li Fermi gases in a three-dimensional box potential [61]. Also, it is interesting to explore an inhomogeneous pairing phase [35,36] and in-medium bound states [62], which cannot be addressed by quantum Monte Carlo simulation due to the sign problem in the mass-and population-imbalanced systems. In order to discuss such phenomena, we need more elaborate estimation of systematic errors.…”

Section: Discussionmentioning

confidence: 99%

Complex Langevin study for polarons in an attractively interacting one-dimensional two-component Fermi gas

Doi,

Tajima,

Tsutsui

2021

Preprint

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We investigate a polaronic excitation in a one-dimensional spin-1/2 Fermi gas with contact attractive interactions, using the complex Langevin method, which is a promising approach to evade a possible sign problem in quantum Monte Carlo simulations. We found that the complex Langevin method works correctly in a wide range of temperature, interaction strength, and population imbalance. The Fermi polaron energy extracted from the two-point imaginary Green's function is not sensitive to the temperature and the impurity concentration in the parameter region we considered. Our results show a good agreement with the solution of the thermodynamic Bethe ansatz at zero temperature.

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In-medium bound states of two bosonic impurities in a one-dimensional Fermi gas

Cited by 25 publications

References 74 publications

Impurities in a one-dimensional Bose gas: the flow equation approach

Impurities in a one-dimensional Bose gas: the flow equation approach

Induced pairing of fermionic impurities in a one-dimensional strongly correlated Bose gas

Complex Langevin study for polarons in an attractively interacting one-dimensional two-component Fermi gas

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