• High-order time expansion path integral ground state 

    Rota, Riccardo; Casulleras Ambrós, Joaquín; Mazzanti Castrillejo, Fernando Pablo; Boronat Medico, Jordi (2010-01)
    Article
    Accés obert
    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 ...
  • On the stability of small vacancy clusters in solid 4He 

    Lutsyshyn, Yaroslav; Rota, Riccardo; Boronat Medico, Jordi (2011-03)
    Article
    Accés restringit per política de l'editorial
    We study numerically properties of multiple vacancies in solid 4He at zero temperature. Up to four vacancies were introduced into the solid through incommensuration between the number of available lattice sites and the ...
  • Path Integral Monte Carlo and Bose-Einstein condensation in quantum fluids and solids 

    Rota, Riccardo (Universitat Politècnica de Catalunya, 2011-12-20)
    Tesi
    Accés obert
    Several microscopic theories point out that Bose-Einstein condensation (BEC), i.e., a macroscopic occupation of the lowest energy single particle state in many-boson systems, may appear also in quantum fluids and solids ...
  • Path integral Monte Carlo calculation of momentum distribution in solid He-4 

    Rota, Riccardo; Boronat Medico, Jordi (2011-02)
    Article
    Accés obert
    We perform calculations of the momentum distribution n(k) in solid 4He by means of path integral Monte Carlo methods.We see that, in perfect crystals, n(k)does not depend on temperature T and that is different from the ...
  • Superfluidity of metastable glassy bulk para-hydrogen at low temperature 

    Osychenko, O.N.; Rota, Riccardo; Boronat Medico, Jordi (2012-06-13)
    Article
    Accés obert
    Molecular para-hydrogen has been proposed theoretically as a possible candidate for superfluidity, but the eventual superfluid transition is hindered by its crystallization. In this work, we study a metastable non ...