K. K. Rajagopal

Scuola Normale Superiore di Pisa, Pisa, Tuscany, Italy

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Publications (6)6.09 Total impact

  • K. K. Rajagopal · P. Vignolo · M. P. Tosi
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    ABSTRACT: Feshbach resonances in a strictly
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    K.K. Rajagopal · P. Vignolo · M.P. Tosi
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    ABSTRACT: We discuss the atom–atom scattering problem across a Feshbach resonance in a two-dimensional dilute Bose gas at zero temperature, in the limit where the s-wave scattering length exceeds the width of the vertical confinement. We determine a tunable coupling-strength parameter and by controlling it we evaluate how the condensate wave function spreads out with increasing atom–atom repulsions. We also discuss the stability of the condensate in the magnetic-field regime where the coupling has become attractive.
    Physica B Condensed Matter 04/2005; 353(1-2-353):59-64. DOI:10.1016/j.physb.2004.09.001 · 1.28 Impact Factor
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    K. K. Rajagopal
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    ABSTRACT: This report is based on my incomplete Phd thesis. The final part of the work on the 2D Yukawa bosons/vortices in a confined geometry is not complete and subject to futher development.
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    K. K. Rajagopal
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    ABSTRACT: A system of N bosons in a two-dimensional harmonic trap is considered. The system is treated in term of the slave boson representation for hard-core bosons which is valid in the arbitrary density regimes. I discuss the consequences of higher order interactions on the density profiles by mapping the slave boson equation to the known Kohn-Sham type equation within the density functional scheme. Comment: 12 pages, 3 figures. Submitted to J. Phys. B : At. mol. opt. phys
    Journal of Physics B Atomic Molecular and Optical Physics 04/2005; DOI:10.1088/0953-4075/38/13/017 · 1.92 Impact Factor
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    K.K. Rajagopal · B. Tanatar · P. Vignolo · M.P. Tosi
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    ABSTRACT: We evaluate the thermodynamic critical angular velocity Ωc(T) for creation of a vortex of lowest quantized angular momentum in a strictly two-dimensional Bose gas at temperature T, using a mean-field two-fluid model for the condensate and the thermal cloud. Our results show that (i) a Thomas–Fermi description of the condensate badly fails in predicting the particle density profiles and the energy of the vortex as functions of T; and (ii) an extrapolation of a simple Thomas–Fermi formula for Ωc(0) is nevertheless approximately useful up to T≃0.5Tc.
    Physics Letters A 09/2004; DOI:10.1016/j.physleta.2004.06.068 · 1.63 Impact Factor
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    K. K. Rajagopal · P. Vignolo · M. P. Tosi
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    ABSTRACT: We study a Bose-condensed gas at finite temperature, in which the particles of the condensate and of the thermal cloud are constrained to move in a plane under radial harmonic confinement and interact via strictly two-dimensional collisions. The coupling parameters are obtained from a calculation of the many-body T-matrix and decreases as temperature increases through a dependence on the chemical potential and on the occupancy of excited states. We discuss the consequences on the condensate fraction and on the density profiles of the condensed and thermal components as functions of temperature, within a simplified form of the two-fluid model. Comment: 12 pages, 4 figures
    Physica B Condensed Matter 09/2003; 344(1-4). DOI:10.1016/j.physb.2003.09.251 · 1.28 Impact Factor