scholarly journals Interplay of nonreciprocity and nonlinearity on mean-field energy and dynamics of a Bose-Einstein condensate in a double-well potential

2021 ◽  
Vol 17 (4) ◽  
Author(s):  
Yi-Piao Wu ◽  
Guo-Qing Zhang ◽  
Cai-Xia Zhang ◽  
Jian Xu ◽  
Dan-Wei Zhang
Keyword(s):  
Mean Field ◽  
Einstein Condensate ◽  
Field Energy ◽  
Bose Einstein Condensate ◽  
Bose Einstein ◽  
Double Well Potential

scholarly journals Bogoliubov theory of a Bose-Einstein condensate of rigid rotor molecules

2021 ◽  
Author(s):  
Joseph C Smith ◽  
Seth T Rittenhouse ◽  
Ryan M Wilson ◽  
Brandon March Peden
Keyword(s):  
Electric Fields ◽  
Density Wave ◽  
Mean Field ◽  
Einstein Condensate ◽  
Field Energy ◽  
Rigid Rotor ◽  
Bogoliubov Theory ◽  
Bose Einstein Condensate ◽  
Plane Component ◽  
Bose Einstein

Abstract We consider a BEC of rigid rotor molecules confined to quasi-2d through harmonic trapping. The molecules are subjected to an external electric field which polarizes the gas, and the molecules interact via dipole-dipole interactions. We present a description of the ground state and low-energy excitations of the system including an analysis of the mean-field energy, polarization, and stability. Under large electric fields the gas becomes fully polarized and we reproduce a well known density-wave instability which arises in polar BECs. Under smaller applied electric fields the gas develops an in-plane polarization leading to the emergence of a new global instability as the molecules “tilt”. The character of these instabilities is clarified by means of momentum-space density-density structure factors. A peak at zero momentum in the spin-spin structure factor for the in-plane component of the polarization indicates that the tilt instability is a global phonon-like instability.

scholarly journals QUANTUM CORRECTIONS TO THE DYNAMICS OF THE BOSE–EINSTEIN CONDENSATE IN A DOUBLE-WELL POTENTIAL

2012 ◽  
Vol 26 (06) ◽  
pp. 1250043 ◽  
Author(s):  
YAN XU ◽  
WEI FAN ◽  
BING CHEN
Keyword(s):  
Mean Field Theory ◽  
Mean Field ◽  
Einstein Condensate ◽  
Matter Wave ◽  
Quantum Corrections ◽  
Bose Einstein Condensate ◽  
Bose Einstein ◽  
Dynamical Instabilities ◽  
Double Well Potential ◽  
Correction Terms

The dynamics of the Bose–Einstein condensate (BEC) in a double-well potential is often investigated under the mean-field theory (MFT). This works successfully for large particle numbers with dynamical stability. But for dynamical instabilities, quantum corrections to the MFT becomes important [J. R. Anglin and A. Vardi, Phys. Rev. A64, 013605 (2001)]. Recently the adiabatic dynamics of the double-well BEC is investigated under the MFT in terms of a dark variable [C. Ottaviani et al., Phys. Rev. A81, 043621 (2010)], which generalizes the adiabatic passage techniques in quantum optics to the nonlinear matter-wave case. We give a fully quantized version of it using second-quantization and introduce new correction terms from higher order interactions beyond the on-site interaction, which are interactions between the tunneling particle and the particle in the well and interactions between the tunneling particles. If only the on-site interaction is considered, this reduces to the usual two-mode BEC.

scholarly journals Derivation of the Landau–Pekar Equations in a Many-Body Mean-Field Limit

2021 ◽  
Vol 240 (1) ◽  
pp. 383-417
Author(s):  
Nikolai Leopold ◽  
David Mitrouskas ◽  
Robert Seiringer
Keyword(s):  
Mean Field ◽  
Einstein Condensate ◽  
Back Reaction ◽  
Many Body ◽  
Field Limit ◽  
Mean Field Limit ◽  
Phonon Field ◽  
Bose Einstein Condensate ◽  
Weakly Couple ◽  
Bose Einstein

AbstractWe consider the Fröhlich Hamiltonian in a mean-field limit where many bosonic particles weakly couple to the quantized phonon field. For large particle numbers and a suitably small coupling, we show that the dynamics of the system is approximately described by the Landau–Pekar equations. These describe a Bose–Einstein condensate interacting with a classical polarization field, whose dynamics is effected by the condensate, i.e., the back-reaction of the phonons that are created by the particles during the time evolution is of leading order.

scholarly journals Two-component axionic dark matter halos

2020 ◽  
Vol 35 (26) ◽  
pp. 2050227 ◽  
Author(s):  
Gennady P. Berman ◽  
Vyacheslav N. Gorshkov ◽  
Vladimir I. Tsifrinovich ◽  
Marco Merkli ◽  
Vladimir V. Tereshchuk
Keyword(s):  
Dark Matter ◽  
Ground State ◽  
Mass Density ◽  
Mean Field ◽  
Einstein Condensate ◽  
Dark Matter Halo ◽  
Bose Einstein Condensate ◽  
Interesting Connection ◽  
Two Component ◽  
Bose Einstein

We consider a two-component dark matter halo (DMH) of a galaxy containing ultra-light axions (ULA) of different mass. The DMH is described as a Bose–Einstein condensate (BEC) in its ground state. In the mean-field (MF) limit, we have derived the integro-differential equations for the spherically symmetrical wave functions of the two DMH components. We studied, numerically, the radial distribution of the mass density of ULA and constructed the parameters which could be used to distinguish between the two- and one-component DMH. We also discuss an interesting connection between the BEC ground state of a one-component DMH and Black Hole temperature and entropy, and Unruh temperature.

Josephson dynamics of strongly interacting superfluid Fermi gases in double-well potentials

2020 ◽  
pp. 2150002
Author(s):  
Ji Li ◽  
Wen Wen ◽  
Yuke Zhang ◽  
Xiaodong Ma
Keyword(s):  
Einstein Condensate ◽  
Interaction Terms ◽  
Bose Einstein Condensate ◽  
Strongly Interacting ◽  
Fermi Superfluids ◽  
The Cross ◽  
Bose Einstein ◽  
Double Well Potential ◽  
Zero Phase ◽  
Superfluid Fermi

In this work, we study the nonlinear Josephson dynamics of Fermi superfluids in the crossover from Bardeen–Cooper–Schrieffer (BCS) superfluid to a molecular Bose-Einstein condensate (BEC) in a double-well potential. Under a two-mode approximation, we derive a full two-mode (fTM) model including all interaction energy terms. By solving the fTM model numerically, we study the zero-phase and [Formula: see text]-phase modes of Josephson oscillations in the BCS–BEC crossover. We find that in the strongly interacting regime the cross interaction terms not appearing in the two-mode model cannot be easily ignored. The cross interactions can alter the behaviors of Josephson dynamics substantially, and interestingly the alterations for the zero-phase and [Formula: see text]-phase modes are just opposite.

scholarly journals Transition from the mean-field to the bosonic Laughlin state in a rotating Bose-Einstein condensate

2019 ◽  
Vol 100 (2) ◽  
Author(s):  
G. Vasilakis ◽  
A. Roussou ◽  
J. Smyrnakis ◽  
M. Magiropoulos ◽  
W. von Klitzing ◽  
...  
Keyword(s):  
Mean Field ◽  
Einstein Condensate ◽  
Bose Einstein Condensate ◽  
The Mean ◽  
Bose Einstein

Nonlinear localized eigenmodes for a Bose–Einstein condensate in a double-well potential

2015 ◽  
Vol 29 (25) ◽  
pp. 1550150
Author(s):  
Qiongtao Xie ◽  
Xiaoliang Liu ◽  
Shiguang Rong
Keyword(s):  
Einstein Condensate ◽  
Localized Modes ◽  
Exact Analytical Solutions ◽  
Bose Einstein Condensate ◽  
Specific Choice ◽  
Asymmetric Distributions ◽  
The Stability ◽  
Bose Einstein ◽  
Double Well Potential ◽  
Potential Parameters

In this paper, we investigate the nonlinear localized eigenmodes for a Bose–Einstein condensate in a double-well potential. For a specific choice of the potential parameters, certain exact analytical solutions for nonlinear localized eigenmodes are presented. By applying the linear stability analysis, the stability regions of these exact nonlinear localized eigenmodes are obtained numerically. It is shown that under certain conditions, the unstable nonlinear localized modes display the breathing behavior characterized by repeated appearance of symmetric and asymmetric distributions in the two potentials. This breathing behavior is shown to arise from the symmetry breaking for these nonlinear localized eigenmodes.

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