Browsing by Author "Seydi, I."

Now showing 1 - 5 of 5

Open Access
Composite quasiparticles in strongly correlated dipolar Fermi liquids
(American Physical Society, 2018) Seydi, I.; Abedinpour, S. H.; Asgari, R.; Tanatar, Bilal
Strong particle-plasmon interaction in electronic systems can lead to composite hole-plasmon excitations. We investigate the emergence of similar composite quasiparticles in ultracold dipolar Fermi liquids originating from the long-range dipole-dipole interaction. We use the G0W technique with an effective interaction obtained from the static structure factor to calculate the quasiparticle properties and single-particle spectral function. We first demonstrate that within this formalism a very good agreement with the quantum Monte Carlo results could be achieved over a wide range of coupling strengths for the renormalization constant and effective mass. The composite quasiparticle-zero sound excitations which are undamped at long wavelengths emerge at intermediate and strong couplings in the spectral function and should be detectable through the radio frequency spectroscopy of nonreactive polar molecules at high densities.
Open Access
Effective mass calculations for two-dimensional gas of dipolar fermions
(Springer New York LLC, 2017) Seydi, I.; Abedinpour, S. H.; Tanatar, Bilal
We consider a two-dimensional system of ultracold dipolar fermions with dipole moments aligned in the perpendicular direction. We use the static structure factor information from Fermi-Hypernetted-Chain calculations to obtain the effective many-body dipole–dipole interaction and calculate the many-body effective mass of the system within the G0W approximation to the self-energy. A large cancellation between different contributions to the self-energy results in a weak dependence of the effective mass on the interaction strength over a large range of coupling constants.
Open Access
Exchange-Correlation effects and the quasiparticle properties in a two-dimensional dipolar fermi liquid
(Springer, 2020) Seydi, I.; Abedinpour, S. H.; Asgari, R.; Tanatar, Bilal
We investigate the effects of exchange and correlation on the quasiparticle properties such as the self-energy, the many-body effective mass and the renormalization constant in a two-dimensional system of ultracold dipolar fermions with dipole moments aligned in the perpendicular direction to the plane. We use the G0W approximation along with the generalized random phase approximation, where the many-body effects have been incorporated in the effective interaction W through the Hubbard local-field factor. The many-body effective mass and the renormalization constant are reduced with the increase of coupling strength. We also study the effect of dipole-dipole interaction on the single-particle spectral function of the two dimensional dipolar Fermi liquid. We observe composite hole-zero sound excitation which is a bound state of quasiparticles with the collective mode (i.e. zero-sound) at intermediate and high coupling constants. These composite excitations are undamped at small wave vectors. Due to repulsion between quasiparticle and composite excitation resonances, we find a gap-like feature between quasiparticle and composite excitation dispersions at long wavelengths.
Open Access
Rotons and Bose condensation in Rydberg-dressed Bose gases
(American Physical Society, 2020) Seydi, I.; Abedinpour, S. H.; Zillich, R. E.; Asgari, R.; Tanatar, Bilal
We investigate the ground-state properties and excitations of Rydberg-dressed bosons in both three and two dimensions, using the hypernetted-chain Euler-Lagrange approximation, which accounts for correlations and thus goes beyond the mean-field approximation. The short-range behavior of the pair distribution function signals the instability of the homogeneous system with respect to the formation of droplet crystals at strong couplings and large soft-core radius. This tendency to spatial density modulation coexists with off-diagonal long-range order. The contribution of the correlation energy to the ground-state energy is significant at large coupling strengths and intermediate values of the soft-core radius while for a larger soft-core radius the ground-state energy is dominated by the mean-field (Hartree) energy. We have also performed path integral Monte Carlo simulations at selected system parameters to verify the performance of our hypernetted-chain Euler-Lagrange results in three dimensions. In the homogeneous phase, the two approaches are in very good agreement. Moreover, Monte Carlo simulations predict a first-order quantum phase transition from a homogeneous superfluid phase to the quantum droplet phase with face-centered cubic symmetry for Rydberg-dressed bosons in three dimensions.
Open Access
Rydberg-dressed Fermi liquid: correlations and signatures of droplet crystallization
(American Physical Society, 2021-04-07) Seydi, I.; Abedinpour, S. H.; Asgari, R.; Panholzer, M.; Tanatar, Bilal
We investigate the effects of many-body correlations on the ground-state properties of a single-component ultracold Rydberg-dressed Fermi liquid with purely repulsive interparticle interactions in both three and two spatial dimensions. We employed the Fermi-hypernetted-chain Euler-Lagrange approximation and observed that the contribution of the correlation energy on the ground-state energy becomes significant at intermediate values of the soft-core radius and large coupling strengths. For small and large soft-core radii, the correlation energy is negligible and the ground-state energy approaches the Hartree-Fock value. The positions of the main peaks in static structure factor and pair distribution function in the homogeneous fluid phase signal the formation of quantum droplet crystals with several particles confined inside each droplet.