MODULATIONAL INSTABILITY OF A BOSE–EINSTEIN CONDENSATE BEYOND THE FERMI PSEUDOPOTENTIAL WITH A TIME-DEPENDENT COMPLEX POTENTIAL

2012 ◽  
Vol 26 (30) ◽  
pp. 1250164 ◽  
Author(s):  
DIDIER BELOBO BELOBO ◽  
GERMAIN HUBERT BEN-BOLIE ◽  
THIERRY BLANCHARD EKOGO ◽  
C. G. LATCHIO TIOFACK ◽  
TIMOLÉON CRÉPIN KOFANÉ
Keyword(s):  
Gravitational Field ◽  
Numerical Simulations ◽  
Complex Potential ◽  
Modulational Instability ◽  
Quantum Fluctuations ◽  
Einstein Condensate ◽  
Time Dependent ◽  
Pitaevskii Equation ◽  
Bose Einstein Condensate ◽  
Bose Einstein

The modulational instability (MI) of Bose–Einstein condensates based on a modified Gross–Pitaevskii equation (GPE) which takes into account quantum fluctuations and a shape-dependent term, trapped in an external time-dependent complex potential is investigated. The external potential consists of an expulsive parabolic background with a complex potential and a gravitational field. The theoretical analysis uses a modified lens-type transformation which converts the modified GPE into a modified form without an explicit spatial dependence. A MI criterion and a growth rate are explicitly derived, both taking into account quantum fluctuations and the parameter related to the feeding or loss of atoms in the condensate which significantly affect the gain of instability of the condensate. Direct numerical simulations of the modified GPE show convincing agreements with analytical predictions. In addition, our numerical results also reveal that the gravitational field has three effects on the MI: (i) the deviation backward or forward of solitons trains, (ii) the enhancement of the appearance of the MI and (iii) the reduction of the lifetime of pulses. Moreover, numerical simulations proved that it is possible to control the propagation of the generated solitons trains by a proper choice of parameters characterizing both the loss or feeding of atoms and the gravitational field, respectively.

DYNAMICS OF NONAUTONOMOUS MATTER BREATHER WAVE IN A TIME-DEPENDENT HARMONIC TRAP WITH NONLINEAR INTERACTION MANAGEMENT

2014 ◽  
Vol 28 (04) ◽  
pp. 1450026 ◽  
Author(s):  
ZHI-GANG LIU ◽  
XIAO-XIAO MA
Keyword(s):  
Nonlinear Interaction ◽  
Complex Potential ◽  
Einstein Condensate ◽  
Time Dependent ◽  
Bose Einstein Condensate ◽  
Parabolic Potential ◽  
Bose Einstein ◽  
Condensate System ◽  
Tunneling Behavior ◽  
Interaction Management

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.

Exact Chirped Soliton Solutions for the One-Dimensional Gross– Pitaevskii Equation with Time-Dependent Parameters

2012 ◽  
Vol 67 (3-4) ◽  
pp. 141-146 ◽  
Author(s):  
Zhenyun Qina ◽  
Gui Mu
Keyword(s):  
Soliton Solution ◽  
Soliton Solutions ◽  
Einstein Condensate ◽  
Time Dependent ◽  
Pitaevskii Equation ◽  
Zero Temperature ◽  
One Dimensional ◽  
Bose Einstein Condensate ◽  
The One ◽  
Bose Einstein

The Gross-Pitaevskii equation (GPE) describing the dynamics of a Bose-Einstein condensate at absolute zero temperature, is a generalized form of the nonlinear Schr¨odinger equation. In this work, the exact bright one-soliton solution of the one-dimensional GPE with time-dependent parameters is directly obtained by using the well-known Hirota method under the same conditions as in S. Rajendran et al., Physica D 239, 366 (2010). In addition, the two-soliton solution is also constructed effectively

scholarly journals Emission of Solitons From an Obstacle Moving in the Bose-Einstein Condensate

2021 ◽  
Vol 9 ◽  
Author(s):  
Yu Song ◽  
Yu Mo ◽  
Shiping Feng ◽  
Shi-Jie Yang
Keyword(s):  
Numerical Simulations ◽  
Einstein Condensate ◽  
Pitaevskii Equation ◽  
Nonlinear Interactions ◽  
One Dimensional ◽  
System Parameters ◽  
Dark Solitons ◽  
Bose Einstein Condensate ◽  
Bose Einstein ◽  
Moving Obstacle

Dark solitons dynamically generated from a potential moving in a one-dimensional Bose-Einstein condensate are displayed. Based on numerical simulations of the Gross-Pitaevskii equation, we find that the moving obstacle successively emits a series of solitons which propagate at constant speeds. The dependence of soliton emission on the system parameters is examined. The formation mechanism of solitons is interpreted as interference between a diffusing wavepacket and the condensate background, enhanced by the nonlinear interactions.PACS numbers: 03.75.Mn, 03.75.Lm, 05.30.Jp

NONAUTONOMOUS DARK SOLITONS IN BOSE–EINSTEIN CONDENSATE

2013 ◽  
Vol 27 (31) ◽  
pp. 1350229 ◽  
Author(s):  
WEI-DONG XIE ◽  
FAN YE ◽  
WANFEN HE ◽  
SHUO FENG ◽  
LI ZHANG
Keyword(s):  
Nonlinear Interaction ◽  
Complex Potential ◽  
Dark Soliton ◽  
Einstein Condensate ◽  
Time Dependent ◽  
Linear Potential ◽  
Arbitrary Time ◽  
Dark Solitons ◽  
Bose Einstein Condensate ◽  
Bose Einstein

In this paper, we study on dark solitons of Bose–Einstein condensate analytically in a time-dependent harmonic trap with an arbitrary time-dependent linear potential and complex potential. It is shown that the nonautonomous dark soliton can be manipulated well through managing external potentials and nonlinear interaction between atoms. We believe that these results would stimulate experiments to manage dark solitons.

scholarly journals Stationary and Dynamical Solutions of the Gross-Pitaevskii Equation for a Bose-Einstein Condensate in a PT symmetric Double Well

10.14311/1797 ◽  
2013 ◽  
Vol 53 (3) ◽  
Author(s):  
Holger Cartarius ◽  
Dennis Dast ◽  
Daniel Haag ◽  
Günter Wunner ◽  
Rüdiger Eichler ◽  
...  
Keyword(s):  
Wave Function ◽  
Three Dimensional ◽  
Stationary Solutions ◽  
Einstein Condensate ◽  
Time Dependent ◽  
Pitaevskii Equation ◽  
One Dimensional ◽  
Bose Einstein Condensate ◽  
Bose Einstein ◽  
Double Well Potential

We investigate the Gross-Pitaevskii equation for a Bose-Einstein condensate in a PT symmetric double-well potential by means of the time-dependent variational principle and numerically exact solutions. A one-dimensional and a fully three-dimensional setup are used. Stationary states are determined and the propagation of wave function is investigated using the time-dependent Gross-Pitaevskii equation. Due to the nonlinearity of the Gross-Pitaevskii equation the potential dependson the wave function and its solutions decide whether or not the Hamiltonian itself is PT symmetric. Stationary solutions with real energy eigenvalues fulfilling exact PT symmetry are found as well as PT broken eigenstates with complex energies. The latter describe decaying or growing probability amplitudes and are not true stationary solutions of the time-dependent Gross-Pitaevskii equation. However, they still provide qualitative information about the time evolution of the wave functions.

PARAMETRIC EXCITATION OF SOLITONS IN DIPOLAR BOSE–EINSTEIN CONDENSATES

2013 ◽  
Vol 27 (25) ◽  
pp. 1350184 ◽  
Author(s):  
A. BENSEGHIR ◽  
W. A. T. WAN ABDULLAH ◽  
B. A. UMAROV ◽  
B. B. BAIZAKOV
Keyword(s):  
Parametric Excitation ◽  
Einstein Condensate ◽  
Quantum Gases ◽  
Variational Approximation ◽  
Pitaevskii Equation ◽  
Nonlocal Nonlinearity ◽  
Bose Einstein Condensate ◽  
Atomic Interactions ◽  
Theoretical Predictions ◽  
Bose Einstein

In this paper, we study the response of a Bose–Einstein condensate with strong dipole–dipole atomic interactions to periodically varying perturbation. The dynamics is governed by the Gross–Pitaevskii equation with additional nonlinear term, corresponding to a nonlocal dipolar interactions. The mathematical model, based on the variational approximation, has been developed and applied to parametric excitation of the condensate due to periodically varying coefficient of nonlocal nonlinearity. The model predicts the waveform of solitons in dipolar condensates and describes their small amplitude dynamics quite accurately. Theoretical predictions are verified by numerical simulations of the nonlocal Gross–Pitaevskii equation and good agreement between them is found. The results can lead to better understanding of the properties of ultra-cold quantum gases, such as 52 Cr , 164 Dy and 168 Er , where the long-range dipolar atomic interactions dominate the usual contact interactions.

Dynamic vortex evolution of harmonically trapped coupled Bose–Einstein condensate with quintic nonlinearity

2021 ◽  
Author(s):  
Yunsong Guo ◽  
Yubin Jiao ◽  
Xiaoning Liu ◽  
Xiangbo Zhu ◽  
Ying Wang
Keyword(s):  
Periodic Breathing ◽  
Oscillation Period ◽  
Angular Frequency ◽  
Equation Model ◽  
Einstein Condensate ◽  
Pitaevskii Equation ◽  
Atomic Systems ◽  
Bose Einstein Condensate ◽  
Two Component ◽  
Bose Einstein

In this study, we investigate the evolution of vortex in harmonically trapped two-component coupled Bose–Einstein condensate with quintic-order nonlinearity. We derive the vortex solution of this two-component system based on the coupled quintic-order Gross–Pitaevskii equation model and the variational method. It is found that the evolution of vortex is a metastable state. The radius of vortex soliton shrinks and expands with time, resulting in periodic breathing oscillation, and the angular frequency of the breathing oscillation is twice the value of the harmonic trapping frequency under infinitesimal nonlinear strength. At the same time, it is also found that the higher-order nonlinear term has a quantitative effect rather than a qualitative impact on the oscillation period. With practical experimental setting, we identify the quasi-stable oscillation of the derived vortex evolution mode and illustrated its features graphically. The theoretical results developed in this work can be used to guide the experimental observation of the vortex phenomenon in ultracold coupled atomic systems with quintic-order nonlinearity.

Phase separation in spin-orbit-angular-momentum coupling Bose–Einstein condensate systems

2020 ◽  
Vol 34 (23) ◽  
pp. 2050241
Author(s):  
Jin Xu ◽  
Jinbin Li
Keyword(s):  
Angular Momentum ◽  
Phase Separation ◽  
Coupling Strength ◽  
Interaction Strength ◽  
Einstein Condensate ◽  
Three Dimensions ◽  
Pitaevskii Equation ◽  
Spin Orbit ◽  
Bose Einstein Condensate ◽  
Bose Einstein

We study the phase separation in three-component spin-orbit-angular-momentum coupled Bose–Einstein condensate with spin-1 in three dimensions. Different types of phase-separation are acquired upon an increase of the coupling strength, magnetic gradient strength, spin-dependent interaction strength and particle number above a critical value. Increasing the value of coupling strength and other related parameters shows distinct behaviors which are produced by repulsion for large strengths of spin-orbit angular-momentum (SOAM) coupling. The present investigation is carried out through a numerical Crank–Nicolson method of the underlying mean-field Gross–Pitaevskii equation.

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