Emulation of the evolution of a Bose–Einstein condensate in a time-dependent harmonic trap

2007 ◽  
Vol 364 (6) ◽  
pp. 497-504 ◽  
Author(s):  
Stavros Theodorakis ◽  
Yiannis Constantinou

Open Physics ◽  
2012 ◽  
Vol 10 (2) ◽  
Author(s):  
Priyanka Verma ◽  
Aranya Bhattacherjee ◽  
Man Mohan

AbstractIn this work, we study parametric excitations in an elongated cigar-shaped BEC in a combined harmonic trap and a time dependent optical lattice by using numerical techniques. We show that there exists a relative competition between the harmonic trap which tries to spatially localize the BEC and the time varying optical lattice which tries to delocalize the BEC. This competition gives rise to parametric excitations (oscillations of the BEC width). Regular oscillations disappear when one of the competing factors, i.e. the strength of harmonic trap or the strength of optical lattice, dominates. Parametric instabilities (chaotic dynamics) arise for large variations in the strength of the optical lattice.



2014 ◽  
Vol 54 (2) ◽  
pp. 116-121 ◽  
Author(s):  
Daniel Haag ◽  
Holger Cartarius ◽  
Günter Wunner

We consider the linear and nonlinear Schrödinger equation for a Bose-Einstein condensate in a harmonic trap with <em>PT</em>-symmetric double-delta function loss and gain terms. We verify that the conditions for the applicability of a recent proposition by Mityagin and Siegl on singular perturbations of harmonic oscillator type self-adjoint operators are fulfilled. In both the linear and nonlinear case we calculate numerically the shifts of the unperturbed levels with quantum numbers n of up to 89 in dependence on the strength of the non-Hermiticity and compare with rigorous estimates derived by those authors. We confirm that the predicted 1/<em>n</em><sup>1/2</sup> estimate provides a valid upper bound on the shrink rate of the numerical eigenvalues. Moreover, we find that a more recent estimate of log(<em>n</em>)/<em>n</em><sup>3/2</sup> is in excellent agreement with the numerical results. With nonlinearity the shrink rates are found to be smaller than without nonlinearity, and the rigorous estimates, derived only for the linear case, are no longer applicable.



2013 ◽  
Vol 8 (3) ◽  
pp. 319-327
Author(s):  
Yu-Ren Shi ◽  
Xue-Ling Wang ◽  
Guang-Hui Wang ◽  
Cong-Bo Liu ◽  
Zhi-Gang Zhou ◽  
...  




2014 ◽  
Vol 28 (04) ◽  
pp. 1450026 ◽  
Author(s):  
ZHI-GANG LIU ◽  
XIAO-XIAO MA

In this paper, we study on breathers of Bose–Einstein condensate analytically in a time-dependent parabolic trap with a complex potential. It is found that the breather can be reflected by the parabolic potential or split into many humps and valleys with the time evolution. The nonlinear tunneling behavior of breather colliding on the parabolic potential is observed. The results provide many possibilities to manipulate breather experimentally in the condensate system.



2007 ◽  
Vol 76 (1) ◽  
Author(s):  
Haydar Uncu ◽  
Devrim Tarhan ◽  
Ersan Demiralp ◽  
Özgür E. Müstecaplıoğlu




Author(s):  
B.M Breid ◽  
J.R Anglin

We describe the time-dependent formation of a molecular Bose–Einstein condensate from a BCS state of fermionic atoms as a result of slow sweeping through a Feshbach resonance. We apply a path integral approach for the molecules, and use two-body adiabatic approximations to solve the atomic evolution in the presence of the classical molecular fields, obtaining an effective action for the molecules. In the narrow resonance limit, the problem becomes semiclassical, and we discuss the growth of the molecular condensate in the saddle point approximation. Considering this time-dependent process as an analogue of the cosmological Zurek scenario, we compare the way condensate growth is driven in this rigorous theory with its phenomenological description via time-dependent Ginzburg–Landau theory.



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