Now showing items 1-20 of 38

    • Berezinskii-Kosterlitz-Thouless transition in two-dimensional dipolar stripes 

      Bombín Escudero, Raul; Mazzanti Castrillejo, Fernando Pablo; Boronat Medico, Jordi (American Physical Society (APS), 2019-12-05)
      Article
      Open Access
      A two-dimensional quantum system of dipoles, with a polarization angle not perpendicular to the plane, shows a transition from a gas to a stripe phase. We have studied the thermal properties of these two phases using the ...
    • Diffusion Monte Carlo methods for spin-orbit-coupled ultracold Bose gases 

      Sánchez Baena, Juan; Boronat Medico, Jordi; Mazzanti Castrillejo, Fernando Pablo (American Physical Society (APS), 2018-11-27)
      Article
      Open Access
      We present two diffusion Monte Carlo (DMC) algorithms for systems of ultracold quantum gases featuring synthetic spin-orbit interactions. The first one is a spin-integrated DMC method which provides fixed-phase energy ...
    • Dilute dipolar quantum droplets beyond the extended Gross-Pitaevskii equation 

      Bötcher, Fabian; Wenzel, Matthias; Schmidt, Jan-Niklas; Guo, Mingyang; Langen, Tim; Ferrier-Barbut, Igor; Pfau, Tilman; Bombín Escudero, Raul; Sánchez Baena, Juan; Boronat Medico, Jordi; Mazzanti Castrillejo, Fernando Pablo (American Physical Society, 2019-11-08)
      Article
      Open Access
      Dipolar quantum droplets are exotic quantum objects that are self-bound due to the subtle balance of attraction, repulsion, and quantum correlations. Here we present a systematic study of the critical atom number of these ...
    • Dipolar Bose Supersolid Stripes 

      Bombín Escudero, Raul; Boronat Medico, Jordi; Mazzanti Castrillejo, Fernando Pablo (2017-12-20)
      Article
      Open Access
      We study the superfluid properties of a system of fully polarized dipolar bosons moving in the XY plane. We focus on the general case where the polarization field forms an arbitrary angle a with respect to the Z axis, ...
    • Droplets of trapped quantum dipolar bosons 

      Macia Rey, Adrián; Sánchez Baena, Juan; Boronat Medico, Jordi; Mazzanti Castrillejo, Fernando Pablo (2016-11-10)
      Article
      Open Access
      Strongly interacting systems of dipolar bosons in three dimensions confined by harmonic traps are analyzed using the exact path integral ground-state Monte Carlo method. By adding a repulsive two-body potential, we find a ...
    • Ferromagnetic transition of a two-component Fermi gas of hard spheres 

      Arias de Saavedra, F.; Mazzanti Castrillejo, Fernando Pablo; Boronat Medico, Jordi; Polls, A. (2012-03-12)
      Article
      Open Access
      We use microscopic many-body theory to analyze the problem of itinerant ferromagnetism in a repulsive atomic Fermi gas of hard spheres. Using simple arguments we show that the available theoretical predictions for the onset ...
    • Few trapped quantum dipoles: quantum versus classical structures 

      Sánchez Baena, Juan; Mazzanti Castrillejo, Fernando Pablo; Boronat Medico, Jordi (2018-01-31)
      Article
      Open Access
      We analyze the ground state of a two-dimensional quantum system of a few strongly confined dipolar bosons. Dipoles arrange in different stable structures that depend on the tilting polarization angle and the anisotropy of ...
    • Gapped spectrum in pair-superfluid bosons 

      Astrakharchik, Grigori; Zillich, Robert E.; Mazzanti Castrillejo, Fernando Pablo; Boronat Medico, Jordi (2016-12-22)
      Article
      Open Access
      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 ...
    • Ground-state properties of a dilute homogeneous Bose gas of hard disks in two dimensions 

      Mazzanti Castrillejo, Fernando Pablo; Polls Martí, Artur; Fabrocini, A (2005-03-10)
      Article
      Open Access
      The energy and structure of a dilute hard-disks Bose gas are studied in the framework of a variational many-body approach based on a Jastrow correlated ground-state wave function. The asymptotic behaviors of the radial ...
    • High-order time expansion path integral ground state 

      Rota, Riccardo; Casulleras Ambrós, Joaquín; Mazzanti Castrillejo, Fernando Pablo; Boronat Medico, Jordi (2010-01)
      Article
      Open Access
      The feasibility of path integral Monte Carlo ground state calculations with very few beads using a high-order short-time Green’s function expansion is discussed. An explicit expression of the evolution operator which provides ...
    • Large-q neutron inclusive-scattering data from liquid 4He 

      Mazzanti Castrillejo, Fernando Pablo; Polls Martí, Artur (American Physical Society (APS), 1998-03-01)
      Article
      Open Access
      We report dynamical calculations for large-q structure functions of liquid 4He at T=1.6 and 2.3 K and compare those with recent MARI data. We extend those calculations far beyond the experimental range q<~29 Å-1 in order ...
    • 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)
      Article
      Open Access
      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 ...
    • Microscopic approach to the response of 3 - 4 He mixtures 

      Fabrocini, A; Mazzanti Castrillejo, Fernando Pablo; Polls Martí, Artur (American Physical Society (APS), 1996-10-01)
      Article
      Open Access
      Correlated-basis-function perturbation theory is used to evaluate the zero-temperature response S(q,¿) of 3-4He mixtures for inelastic neutron scattering, at momentum transfers q ranging from 1.1 to 1.8 A°-1. We adopt a ...
    • Microscopic description of anisotropic low-density dipolar Bose gases in two dimensions 

      Macia Rey, Adrián; Mazzanti Castrillejo, Fernando Pablo; Boronat Medico, Jordi; Zillich, R.E. (2011-09-19)
      Article
      Open Access
      A microscopic description of the zero-energy two-body ground state and many-body static properties of anisotropic homogeneous gases of bosonic dipoles in two dimensions at low densities is presented and discussed. By ...
    • Neighborhood-based stopping criterion for contrastive divergence 

      Romero Merino, Enrique; Mazzanti Castrillejo, Fernando Pablo; Delgado Pin, Jordi (2018-07)
      Article
      Open Access
      Restricted Boltzmann Machines (RBMs) are general unsupervised learning devices to ascertain generative models of data distributions. RBMs are often trained using the Contrastive Divergence (CD) learning algorithm, an ...
    • Nucleation of helium in liquid lithium at 843 K and high pressures 

      Martí Rabassa, Jordi; Mazzanti Castrillejo, Fernando Pablo; Astrakharchik, Grigori; Batet Miracle, Lluís; Portos-Amill, Laura; Pedreño, Borja (Multidisciplinary Digital Publishing Institute (MDPI), 2022-04-13)
      Article
      Open Access
      Fusion energy stands out as a promising alternative for a future decarbonised energy system. In order to be sustainable, future fusion nuclear reactors will have to produce their own tritium. In the so-called breeding ...
    • Nucleation of helium in pure liquid lithium 

      Álvarez Galera, Edgar; Martí Rabassa, Jordi; Mazzanti Castrillejo, Fernando Pablo; Batet Miracle, Lluís (American Institute of Physics (AIP), 2023-07-14)
      Article
      Open Access
      Tritium self-sufficiency in fusion nuclear reactors will be based on the neutron capture by lithium in the so-called breeding blankets of the reactor, a nuclear reaction that will produce helium along with tritium. The low ...
    • Off-diagonal long-range order in arrays of dipolar droplets 

      Bombín Escudero, Raul; Mazzanti Castrillejo, Fernando Pablo; Boronat Medico, Jordi (Institute of Physics (IOP), 2024-01-01)
      Article
      Open Access
      We report quantum Monte Carlo results of harmonically confined quantum Bose dipoles within a range of interactions covering the evolution from a gas phase to the formation of an array of droplets. Scaling the experimental ...
    • One-dimensional Bose gas in optical lattices of arbitrary strength 

      Astrakharchik, Grigori; Krutitsky, K.V.; Lewenstein, Maciej; Mazzanti Castrillejo, Fernando Pablo (2016-02-08)
      Article
      Open Access
      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 harmonically confined SU(N) fermions 

      Gordillo Bargueño, Maria Carmen; Mazzanti Castrillejo, Fernando Pablo; Boronat Medico, Jordi (American Physical Society (APS), 2019-08-05)
      Article
      Open Access
      We study the momentum distributions and spatial correlations of few harmonically confined SU(N) fermions using quantum Monte Carlo methods. In our study, we vary the spin degeneracy N from 2 to 6 and the total number of ...