Ara es mostren els items 1-20 de 49

    • Bose polarons in ultracold atoms in one dimension: beyond the Fröhlich paradigm 

      Grusdt, Fabian; Astrakharchik, Grigori; Demler, Eugene (2017-10-25)
      Article
      Accés obert
      Mobile impurity atoms immersed in Bose–Einstein condensates provide a new platform for exploring Bose polarons. Recent experimental advances in the field of ultracold atoms make it possible to realize such systems with ...
    • Bose-Einstein condensate comagnetometer 

      Mazzinghi, Chiara; Gómez Kabelka, Pau; Martin, Ferran; Benedicto Orenes, Daniel; Palacios, Silvana; Mitchell, Morgan W. (American Institute of Physics (AIP), 2020-04-29)
      Article
      Accés obert
      We describe a comagnetometer employing the f ¼ 1 and f ¼ 2 ground state hyperfine manifolds of a 87Rb spinor Bose-Einstein condensate as colocated magnetometers. The hyperfine manifolds feature nearly opposite gyromagnetic ...
    • Bose-Einstein condensates with localized spin-orbit coupling: Soliton complexes and spinor dynamics 

      Kartashov, Yaroslav; Konotop, Vladimir V; Zezyulin, Dmitry A (2014-12-15)
      Article
      Accés obert
      Spin-orbit (SO) coupling can be introduced in a Bose-Einstein condensate (BEC) as a gauge potential acting only in a localized spatial domain. The effect of such a SO “defect” can be understood by transforming the system to ...
    • Bose-Hubbard model of a Bose-Einstein condensate in a double-well 

      Melé Messeguer, Marina (Universitat Politècnica de Catalunya, 2010-07-19)
      Projecte Final de Màster Oficial
      Accés obert
      We study the static and dynamic behavior of a Bose-Einstein condensate in a double-well potential in the framework of the Bose-Hubbard model. Particular attention is devoted to analyze the structure of the ground state ...
    • Collective excitations of a one-dimensional quantum droplet 

      Tylutki, Marek; Astrakharchik, Grigori; Malomed, Boris A.; Petrov, D. S. (2020-05-21)
      Article
      Accés obert
      We calculate the excitation spectrum of a one-dimensional self-bound quantum droplet in a two-component bosonic mixture described by the Gross-Pitaevskii equation (GPE) with cubic and quadratic nonlinearities. The cubic ...
    • Compactons and bistability in exciton-polariton condensates 

      Kartashov, Yaroslav V.; Konotop, Vladimir V; Torner Sabata, Lluís (2012-11-15)
      Article
      Accés obert
      We address stationary patterns in exciton-polariton condensates supported by a narrow external pump beam, and we discover that even in the absence of trapping potentials, such condensates may support stable localized stationary ...
    • Composite boson description of a low-density gas of excitons 

      Golomedov, A. E.; Lozovik, Yu. E.; Astrakharchik, Grigori; Boronat Medico, Jordi (2017-10-13)
      Article
      Accés obert
      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 ...
    • Correlation properties of a one-dimensional repulsive Bose gas at finite temperature 

      Rosi, Giulia de; Rota, Riccardo; Astrakharchik, Grigori; Boronat Medico, Jordi (2023-04-05)
      Article
      Accés obert
      We present a comprehensive study shedding light on how thermal fluctuations affect correlations in a Bose gas with contact repulsive interactions in one spatial dimension. The pair correlation function, the static structure ...
    • Density functional approach in the study of Bose-Bose liquid drops 

      Sanuy Latorre, Ares (Universitat Politècnica de Catalunya, 2022-10-28)
      Projecte Final de Màster Oficial
      Accés obert
      We have studied quantum liquid drops composed by a mixture of two Bose components using a density-functional formulation. The functional has been built following two different methods: the beyond mean-field Lee-Huang-Yang ...
    • Dilute quantum Bose gases beyond its limit of universality 

      Planasdemunt Hospital, Martí (Universitat Politècnica de Catalunya, 2023-07-10)
      Treball Final de Grau
      Accés obert
      The Bose equation of state has not progressed significantly since the universality regime discovery in terms of the s-wave scattering length, a. Nowadays no expansion exists to calculate the energy at higher densities, ...
    • Dipolar Bose Supersolid Stripes 

      Bombín Escudero, Raul; Boronat Medico, Jordi; Mazzanti Castrillejo, Fernando Pablo (2017-12-20)
      Article
      Accés obert
      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, ...
    • Dynamics of a Bose Einstein condensate in a ring potential 

      Pino Quintana, Hernán (Universitat Politècnica de Catalunya / Universitat Autònoma de Barcelona, 2012-09-04)
      Projecte Final de Màster Oficial
      Accés obert
      [ANGLÈS] We have addressed the dynamics of a repulsive interacting 87 Rb Bose Einstein condensate (BEC) in a ring potential trap. Our study has been focused in the analysis of the interference pattern that arises by the ...
    • Dynamics of one-dimensional quantum droplets 

      Astrakharchik, Grigori; Malomed, Boris A. (American Physical Society (APS), 2018-07-30)
      Article
      Accés obert
      The structure and dynamics of one-dimensional binary Bose gases forming quantum droplets is studied by solving the corresponding amended Gross-Pitaevskii equation. Two physically different regimes are identified, corresponding ...
    • Estimation of the condensate fraction from the static structure factor 

      Lozovik, Yu. E.; Kurbakov, I. L.; Astrakharchik, Grigori; Boronat Medico, Jordi (American Physical Society (APS), 2021-03-16)
      Article
      Accés obert
      We present an analytical method to estimate the condensate fraction n0/n in strongly correlated systems for which the zero-temperature static structure factor S(p) is known. The advantage of the proposed method is that it ...
    • Few trapped quantum dipoles: quantum versus classical structures 

      Sánchez Baena, Juan; Mazzanti Castrillejo, Fernando Pablo; Boronat Medico, Jordi (2018-01-31)
      Article
      Accés obert
      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 ...
    • Gap solitons in a spin-orbit-coupled bose-einstein condensate 

      Kartashov, Yaroslav V.; Konotop, Vladimir V; Abdullaev, Fatkhulla Kh (2013-08)
      Article
      Accés obert
      We report a diversity of stable gap solitons in a spin-orbit-coupled Bose-Einstein condensate subject to a spatially periodic Zeeman field. It is shown that the solitons can be classified by the main physical symmetries ...
    • 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
      Accés obert
      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 ...
    • Heating a dipolar quantum fluid into a solid 

      Sánchez Baena, Juan; Politi, Claudia; Maucher, Fabian; Ferlaino, Francesca; Pohl, Thomas (2023-04-04)
      Article
      Accés obert
      Raising the temperature of a material enhances the thermal motion of particles. Such an increase in thermal energy commonly leads to the melting of a solid into a fluid and eventually vaporises the liquid into a gaseous ...
    • Interferometric measurement of interhyperfine scattering lengths in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mmultiscripts><mml:mi>Rb</mml:mi><mml:mprescripts /><mml:none /><mml:mn>87</mml:mn></mml:mmultiscripts></mml:math> 

      Mazzinghi, Chiara; Gómez Kabelka, Pau; Martin, Ferran; Coop, Simon; Palacios, Silvana; Mitchell, Morgan W. (American Physical Society (APS), 2019-09-10)
      Article
      Accés obert
      We present interferometeric measurements of the f = 1 to f = 2 interhyperfine scattering lengths in a single-domain spinor Bose-Einstein condensate of 87Rb. The interhyperfine interaction leads to a strong and state-dependent ...
    • Ionic polaron in a Bose-Einstein condensate 

      Astrakharchik, Grigori; Schmidt, Richard (2021-05-11)
      Article
      Accés obert
      The presence of strong interactions in a many-body quantum system can lead to a variety of exotic effects. Here we show that even in a comparatively simple setup consisting of a charged impurity in a weakly interacting ...