UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS

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2022-07-01 17:52

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Conference: Bucharest University Faculty of Physics 2019 Meeting


Section: Theoretical Physics and Applied Mathematics


Title:
Discrete nonlinear Schrödinger equations for high density Bose-Einstein condensates loaded into optical lattices


Authors:
Emanuela BOICU (1), Mihaela Carina RAPORTARU (2), Alexandru I. NICOLIN (1,2)


Affiliation:
1) Faculty of Physics, University of Bucharest, Atomistilor 405, Magurele, Romania

2) Department of Computational Physics and Information Technologies,

Horia Hulubei National Institute for Physics and Nuclear Engineering, Reactorului 30, Magurele, Romania



E-mail
nicolin@nicolin.info


Keywords:
Bose-Einstein condensates, discrete models


Abstract:
We derive by analytical means a new set of discrete nonlinear Schrödinger (DNLS) equations using the Gross-Pitaevskii 0 K equation for the dynamics of a high-density Bose-Einstein condensates loaded into a deep optical lattice [1]. The derived equations take into account the changes in the density profile of the wave function in each well of the potential through the versatile q-Gaussian local ansatz of the condensate wave function. The q-parameter of the ansatz allows a description of the entire density regime of the condensate, from low- to high-densities [2]. We compare our equation with those previously used for low-density condensates loaded into optical lattices [3].


References:

1. V.S. Bagnato et al., Bose-Einstein condensation: Twenty Years After, Rom. Rep. Phys. 67, 1, 5 (2015).

2. A.I. Nicolin and R. Carretero-González, Nonlinear dynamics of Bose-condensed gases by means of a q-Gaussian variational approach, Physica A 387, 24, 6032 (2008).

3. A. Smerzi and A. Trombettoni, Nonlinear tight-binding approximation for Bose-Einstein condensates in a lattice, Phys. Rev. A 68, 023613 (2003).



Acknowledgement:
The work of M.C. Raportaru and A. I. Nicolin is funded by Romanian Ministry of Education through project PN 19060205/2019.