Ara es mostren els items 26-45 de 58

    • 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)
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      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 ...
    • One dimensional H-1, H-2 and H-3 

      Vidal, A.J.; Astrakharchik, Grigori; Vranješ Markic, Leandra; Boronat, J. (2016-05-26)
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      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)
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      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)
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      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, ...
    • One-dimensional three-boson problem with two- and three-body interactions 

      Guijarro Gámez, Grecia; Pricoupenko, A.; Astrakharchik, Grigori; Boronat Medico, Jordi; Petrov, D. S. (American Physical Society (APS), 2018-06-14)
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      We solve the three-boson problem with contact two- and three-body interactions in one dimension and analytically calculate the ground and excited trimer-state energies. Then, by using the diffusion Monte Carlo technique, ...
    • 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)
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      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)
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    • Phase diagram of quasi-two-dimensional bosons in a laser-speckle potential 

      Astrakharchik, Grigori; Krutitsky, K.V.; Navez, Patrick (2013-06)
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      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 ...
    • Polaron interactions and bipolarons in one-dimensional Bose bases in the strong coupling regime 

      Astrakharchik, Grigori (American Institute of Physics (AIP), 2021-09-03)
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      Bose polarons, quasiparticles composed of mobile impurities surrounded by cold Bose gas, can experience strong interactions mediated by the many-body environment and form bipolaron bound states. Here we present a detailed ...
    • 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)
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      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 halo states in two-dimensional dipolar clusters 

      Guijarro Gámez, Grecia; Astrakharchik, Grigori; Boronat Medico, Jordi (Nature, 2021-12-01)
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      A halo is an intrinsically quantum object defined as a bound state of a spatial size which extends deeply into the classically forbidden region. Previously, halos have been observed in bound states of two and less frequently ...
    • Quantum phase transition of a two-dimensional quadrupolar system 

      Astrakharchik, Grigori; Kurbakov, I. L.; Lozovik, Yu. E. (American Physical Society (APS), 2021-04-01)
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      Ensembles with long-range interactions between particles are promising for revealing strong quantum collective effects and many-body phenomena. Here we study the ground-state phase diagram of a two-dimensional Bose system ...
    • Quantum phase transition with a simple variational ansatz 

      Lutsyshyn, Yaroslav; Astrakharchik, Grigori; Cazorla, C; Boronat Medico, Jordi (2014-12-11)
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      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)
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      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)
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      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)
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      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)
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      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 ...
    • Spin dynamics and Andreev-Bashkin effect in mixtures of one-dimensional Bose gases 

      Parisi, L.; Astrakharchik, Grigori; Giorgini, Stefano (American Institute of Physics (AIP), 2018-07-11)
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      We investigate the propagation of spin waves in two-component mixtures of one-dimensional Bose gases interacting through repulsive contact potentials. By using quantum Monte Carlo methods we calculate static ground-state ...
    • Strong coupling Bose polarons in a two-dimensional gas 

      Peña Ardila, Luis Aldemar; Astrakharchik, Grigori; Giorgini, Stefano (American Physical Society, 2020-06-26)
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      We study the properties of Bose polarons in two dimensions using quantum Monte Carlo techniques. Results for the binding energy, the effective mass, and the quasiparticle residue are reported for a typical strength of ...
    • Superexchange liquefaction of strongly correlated lattice dipolar bosons 

      Morera Navarro, Iván; Oldziejewski, Rafal; Astrakharchik, Grigori; Julia Diaz, Bruno (American Institute of Physics (AIP), 2023-01-12)
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      We propose a mechanism for liquid formation in strongly correlated lattice systems. The mechanism is based on an interplay between long-range attraction and superexchange processes. As an example, we study dipolar bosons ...