• Composite boson description of a low-density gas of excitons 

    Golomedov, A. E.; Lozovik, Yu. E.; Astrakharchik, Grigori; Boronat Medico, Jordi (2017-10-13)
    Artículo
    Acceso restringido por política de la editorial
    Ground-state properties of a fermionic Coulomb gas are calculated using the fixed-node diffusion Monte Carlo method. The validity of the composite boson description is tested for different densities. We extract the ...
  • Distinguishability, degeneracy, and correlations in three harmonically trapped bosons in one dimension 

    Garcia March, Miguel Angel; Julia Diaz, Bruno; Astrakharchik, Grigori; Boronat Medico, Jordi; Polls, A. (2014-12-01)
    Artículo
    Acceso abierto
    We study a system of two bosons of one species and a third atom of a second species in a one-dimensional parabolic trap at zero temperature. We assume contact repulsive inter- and intraspecies interactions. By means of an ...
  • Dynamic structure function of a cold Fermi gas at unitarity 

    Astrakharchik, Grigori; Boronat Medico, Jordi; Krotscheck, Eckhard; Lichtenegger, Thomas (Institute of Physics (IOP), 2014-08-14)
    Artículo
    Acceso abierto
    We present a theoretical study of the dynamic structure function of a resonantly interacting two-component Fermi gas at zero temperature. Our approach is based on dynamic many-body theory able to describe excitations in ...
  • Exact ground-state properties of a one-dimensional Coulomb gas 

    Astrakharchik, Grigori; Girardeau, M.D. (2011-04-15)
    Artículo
    Acceso abierto
    The ground-state properties of a single-component one-dimensional Coulomb gas are investigated. We use Bose-Fermi mapping for the ground-state wave function which permits solution of the Fermi sign problem in the following ...
  • Gapped spectrum in pair-superfluid bosons 

    Astrakharchik, Grigori; Zillich, Robert E.; Mazzanti Castrillejo, Fernando Pablo; Boronat Medico, Jordi (2016-12-22)
    Artículo
    Acceso abierto
    We study the ground state of a bilayer system of dipolar bosons with dipoles oriented by an external field perpendicularly to the two parallel planes. By decreasing the interlayer distance, for a fixed value of the strength ...
  • Low-dimensional weakly interacting Bose gases: nonuniversal equations of state 

    Astrakharchik, Grigori; Boronat Medico, Jordi; Kurbakov, I L; Lozovik, Y E; Mazzanti Castrillejo, Fernando Pablo (2010-01)
    Artículo
    Acceso abierto
    The zero-temperature equation of state is analyzed in low-dimensional bosonic systems. We propose to use the concept of energy-dependent s-wave scattering length for obtaining estimations of nonuniversal terms in the energy ...
  • Luttinger-liquid behavior of one-dimensional He-3 

    Astrakharchik, Grigori; Boronat Medico, Jordi (2014-12-30)
    Artículo
    Acceso abierto
    The ground-state properties of one-dimensional He-3 are studied using quantum Monte Carlo methods. The equation of state is calculated in a wide range of physically relevant densities and is well interpolated by a power-series ...
  • One dimensional H-1, H-2 and H-3 

    Vidal, A.J.; Astrakharchik, Grigori; Vranješ Markic, Leandra; Boronat, J. (2016-05-26)
    Artículo
    Acceso abierto
    The ground-state properties of one-dimensional electron-spin-polarized hydrogen H-1, deuterium H-2, and tritium 3 Hare obtained by means of quantum Monte Carlo methods. The equations of state of the three isotopes are ...
  • One-dimensional Bose gas in optical lattices of arbitrary strength 

    Astrakharchik, Grigori; Krutitsky, K.V.; Lewenstein, Maciej; Mazzanti Castrillejo, Fernando Pablo (2016-02-08)
    Artículo
    Acceso abierto
    One-dimensional Bose gas with contact interaction in optical lattices at zero temperature is investigated by means of the exact diffusion Monte Carlo algorithm. The results obtained from the fundamental continuous model ...
  • One-dimensional multicomponent Fermi gas in a trap: quantum Monte Carlo study 

    Matveeva, N.; Astrakharchik, Grigori (2016-06-22)
    Artículo
    Acceso abierto
    A one-dimensional world is very unusual as there is an interplay between quantum statistics and geometry, and a strong short-range repulsion between atoms mimics Fermi exclusion principle, fermionizing the system. Instead, ...
  • Optical lattices as a tool to study defect-induced superfluidity 

    Astrakharchik, Grigori; Krutitsky, K.V.; Lewenstein, Maciej; Mazzanti Castrillejo, Fernando Pablo; Boronat Medico, Jordi (AMER PHYSICAL SOC, 2017-09-05)
    Artículo
    Acceso abierto
    We study the superfluid response, the energetic and structural properties of a one-dimensional ultracold Bose gas in an optical lattice of arbitrary strength. We use the Bose-Fermi mapping in the limit of infinitely large ...
  • Phase diagram of a quantum Coulomb wire 

    Ferré Porta, Guillem; Astrakharchik, Grigori; Boronat Medico, Jordi (2015-12-09)
    Artículo
    Acceso abierto
  • Phase diagram of quasi-two-dimensional bosons in a laser-speckle potential 

    Astrakharchik, Grigori; Krutitsky, K.V.; Navez, Patrick (2013-06)
    Artículo
    Acceso abierto
    We have studied the phase diagram of a quasi-two-dimensional interacting Bose gas at zero temperature in the presence of random potential created by laser speckles. The superfluid fraction and the fraction of particles ...
  • Quantum correlations and spatial localization in one-dimensional ultracold bosonic mixtures 

    Garcia March, Miguel Angel; Julia Diaz, Bruno; Astrakharchik, Grigori; Busch, Th; Boronat Medico, Jordi; Polls, A. (2014-10-07)
    Artículo
    Acceso abierto
    We present the complete phase diagram for one-dimensional binary mixtures of bosonic ultracold atomic gases in a harmonic trap. We obtain exact results with direct numerical diagonalization for a small number of atoms, ...
  • Quantum phase transition with a simple variational ansatz 

    Lutsyshyn, Yaroslav; Astrakharchik, Grigori; Cazorla, C; Boronat Medico, Jordi (2014-12-11)
    Artículo
    Acceso abierto
    We study the zero-temperature quantum phase transition between liquid and hcp solid He-4. We use the variational method with a simple yet exchange-symmetric and fully explicit wave function. It is found that the optimized ...
  • Quantum versus mean-field collapse in a many-body system 

    Astrakharchik, Grigori; Malomed, Boris A. (2015-10-29)
    Artículo
    Acceso abierto
    The recent analysis, based on the mean-field approximation (MFA), has predicted that the critical quantum collapse of the bosonic wave function, pulled to the center by the inverse-square potential in the three-dimensional ...
  • Reentrant behavior of the breathing-mode-oscillation frequency in a one-dimensional Bose gas 

    Gudyma, A; Astrakharchik, Grigori; Zvonarev, Mikhail (2015-08-07)
    Artículo
    Acceso abierto
    Exciting temporal oscillations of the density distribution is a high-precision method for probing ultracold trapped atomic gases. Interaction effects in their many-body dynamics are particularly puzzling and counter-intuitive ...
  • Sharp crossover from composite fermionization to phase separation in microscopic mixtures of ultracold bosons 

    Garcia March, Miguel Angel; Julia Diaz, Bruno; Astrakharchik, Grigori; Busch, T; Boronat Medico, Jordi; Rios Polls, Artur (2013-12-03)
    Artículo
    Acceso abierto
    We show that a two-component mixture of a few repulsively interacting ultracold atoms in a one-dimensional trap possesses very diverse quantum regimes and that the crossover between them can be induced by tuning the ...
  • Single-particle versus pair superfluidity in a bilayer system of dipolar bosons 

    Macia Rey, Adrián; Astrakharchik, Grigori; Mazzanti Castrillejo, Fernando Pablo; Giorgini, Stefano; Boronat Medico, Jordi (2014-10-21)
    Artículo
    Acceso abierto
    We consider the ground state of a bilayer system of dipolar bosons, where dipoles are oriented by an external field in the direction perpendicular to the parallel planes. Quantum Monte Carlo methods are used to calculate ...
  • Thermodynamic behavior of a one-dimensional Bose gas at low temperature 

    de Rosi, Giulia; Astrakharchik, Grigori; Stringari, Sandro (AMER PHYSICAL SOC, 2017-07-11)
    Artículo
    Acceso abierto
    We show that the chemical potential of a one-dimensional (1D) interacting Bose gas exhibits a nonmonotonic temperature dependence which is peculiar of superfluids. The effect is a direct consequence of the phononic nature ...