Related papers: Collective mode across the BCS-BEC crossover in Ho…
The pairing of interacting fermions leading to superfluidity has two limiting regimes: the Bardeen-Cooper-Schrieffer (BCS) scheme for weakly interacting degenerate fermions and the Bose-Einstein condensation (BEC) of bosonic pairs of…
We study the effect of lower dimensional geometry on the frequencies of the collective oscillations of a Bose-Einstein condensate confined in a trap. To study the effect of two dimensional geometry we consider a pancake-shaped condensate…
Based on a unified theoretical treatment of the 1D Bogoliubov-de Genes equations, the superfluidity phenomenon of the Bose-Einstein condensates (BEC) loaded into trapped optical lattice is studied. Within the perturbation regime, an…
We explore the formation and collective modes of Bose-Einstein condensate of Dirac magnons (Dirac BEC). While we focus on two-dimensional Dirac magnons, an employed approach is general and could be used to describe Bose-Einstein condensates…
We investigate the superconducting (SC), charge-density wave (CDW), and antiferromagnetic (AFM) phases in the extended Hubbard model at zero temperature and half-filling. We employ the iterated equations of motion approach to compute the…
We study soliton collisions and the decay of solitons into sound in superfluid Fermi gases across the Bose-Einstein condensate to Bardeen-Cooper-Schrieffer (BEC-BCS) crossover by performing numerical simulations of the time-dependent…
The exchange of collective modes has been demonstrated to be a powerful tool for inducing superconductivity and superfluidity in various condensed matter and atomic systems. In this article, we study the mediated interactions of collective…
We study the three-dimensional U(1) lattice gauge theory of a CP$^1$ spinon (Schwinger boson) field and a Higgs field. It is a bosonic $t$-$J$ model in slave-particle representation, describing the antiferromagnetic (AF) Heisenberg spin…
We discuss the BCS-BEC crossover in a degenerate Fermi gas of two hyperfine states interacting close to a Feshbach resonance. This system has quasi-molecular Bosons associated with a Feshbach resonance, and this kinds of coupled…
Dilute gas Bose-Einstein condensates (BEC's), currently used to cool fermionic atoms in atom traps, can also probe the superfluidity of these fermions. The damping rate of BEC-acoustic excitations (phonon modes), measured in the middle of…
In one dimension the coupling of electrons to phonons leads to a transition from a metallic to a Peierls distorted insulated state if the coupling exceeds a critical value. On the other hand, in two dimensions the electron-phonon…
The role of collective modes in various experiments on the cuprates is investigated. We calculate the neutron scattering, photoemission (ARPES), and Raman scattering intensities below $T_c$ within the fluctuation-exchange (FLEX)…
The Holstein Model (HM) describes the interaction between fermions and a collection of local (dispersionless) phonon modes. In the dilute limit, the phonon degrees of freedom dress the fermions, giving rise to polaron and bipolaron…
We investigate the bipolaronic crossover and the pairing transition for a two-orbital model with Jahn-Teller coupling to a two-fold degenerate phonon mode. The evolution from weak to strong coupling is reminiscent of the behavior of the…
The transition from weakly damped coherent motion to localization in the context of the spin-boson model has been the subject of numerous studies with distinct behavior depending on the form of the phonon-bath spectral density,…
We analyze the theoretical derivation of the beyond-mean-field equation of state for a two-dimensional gas of dilute, ultracold alkali-metal atoms in the Bardeen-Cooper-Schrieffer (BCS) to Bose-Einstein condensate (BEC) crossover. We show…
The search for realistic one-dimensional (1D) models that exhibit dominant superconducting (SC) fluctuations effects has a long history. In these 1D systems, the effects of commensurate band fillings--strongest at half-filling--and…
The Bardeen-Cooper-Schrieffer (BCS)-Bose-Einstein condensation (BEC) crossover in the two-dimensional attractive Hubbard model under the magnetic field is discussed at the half-filling at T=0 K on the basis of the formalism of Eagles and…
We have demonstrated that it is possible to access a crossover scenario starting with a weak coupling (BCS) d-wave superconductor to a strongly coupled Bose-Einstein condensate (BEC) phase as the exchange interaction is tuned in a two…
We present a stability analysis on a driven-dissipative electron-hole condensate in the BCS (Bardeen-Cooper-Schrieffer)-BEC (Bose-Einstein-condensation)-crossover region. Extending the combined BCS-Leggett theory with the generalized random…