Dynamical instability of a Bose-Einstein condensate with higher-order interactions in an optical potential through a variational approach

E Wamba; S Sabari; K Porsezian; A Mohamadou; T C Kofané

doi:10.1103/PhysRevE.89.052917

Dynamical instability of a Bose-Einstein condensate with higher-order interactions in an optical potential through a variational approach

Phys Rev E Stat Nonlin Soft Matter Phys. 2014 May;89(5):052917. doi: 10.1103/PhysRevE.89.052917. Epub 2014 May 29.

Authors

E Wamba¹, S Sabari², K Porsezian², A Mohamadou³, T C Kofané⁴

Affiliations

¹ Department of Physics, Faculty of Science, University of Yaoundé I, P. O. Box 812, Yaoundé, Cameroon and African Institute for Mathematical Sciences, 6 Melrose Road, Muizenberg, 7945, South Africa.
² Department of Physics, Pondicherry University, Puducherry 605014, India.
³ Department of Physics, Faculty of Science, University of Douala, P. O. Box 24157, Douala, Cameroon and The Abdus Salam International Centre for Theoretical Physics, P. O. Box 586, Strada Costiera 11, I-34014, Trieste, Italy.
⁴ Department of Physics, Faculty of Science, University of Yaoundé I, P. O. Box 812, Yaoundé, Cameroon.

PMID: 25353871
DOI: 10.1103/PhysRevE.89.052917

Abstract

We investigate the dynamical instability of Bose-Einstein condensates (BECs) with higher-order interactions immersed in an optical lattice with weak driving harmonic potential. For this, we compute both analytically and numerically a modified Gross-Pitaevskii equation with higher-order nonlinearity and external potentials generated by magnetic and optical fields. Using the time-dependent variational approach, we derive the ordinary differential equations for the time evolution of the amplitude and phase of modulational perturbation. Through an effective potential, we obtain the modulational instability condition of BECs and discuss the effect of the higher-order interaction in the dynamics of the condensates in presence of optical potential. We perform direct numerical simulations to support our analytical results, and good agreement is found.