Stability of trapped degenerate dipolar Bose and Fermi gases

Adhikari, Sadhan K.

doi:10.1088/0953-4075/46/11/115301

Cited by 5 publications

(6 citation statements)

References 51 publications

(103 reference statements)

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“…(7) it appears that such modes have an azimuthal dependence proportional to sin(3φ) and sin(4φ): the condensate is thus expected to collapse with density modulations in the angular coordinates which breaks the cylindrical symmetry. A similar breaking pattern has also been observed in the collapse of harmonically trapped Bose clouds in pancake-shaped condensates from numerical simulations based on the GP equation [28].…”

Section: Resultssupporting

confidence: 78%

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Dipolar Bose gas in a highly anharmonic trap

Ancilotto

Toigo

2014

Phys. Rev. A

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By means of mean-field theory, we have studied the structure and excitation spectrum of a purely dipolar Bose gas in a pancake shaped trap where the confinement in the x-y plane is provided by a highly anharmonic potential, resulting in an almost uniform confinement in the plane. We show that the stable condensates are characterized by marked radially structured density profiles. The stability diagram is calculated by independently varying the strength of the interaction and the trap geometry. By computing the Bogoliubov excitation spectrum near the instability line we show that soft “angular” rotons are responsible for the collapse of the system. The free expansion of the cloud after the trap is released is also studied by means of time-dependent calculations, showing that a prolate cigar-shaped condensate is dynamically stabilized during the expansion, which would otherwise collapse. Dipolar condensates rotating with sufficiently high angular velocity show the formation of multiply quantized giant vortices, while the condensates acquire a ring-shaped form

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Section: Resultssupporting

confidence: 78%

“…The collapse of disc-shaped Bose dipolar gases has also been numerically studied in real-time dynamics in Ref. [28].…”

Section: Introductionmentioning

confidence: 99%

Dipolar Bose gas in a highly anharmonic trap

Ancilotto

Toigo

2014

Phys. Rev. A

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“…In tensor notations it can be presented as E α ji = d β i ∇ β ∇ α (1/r). Let us have a look on the differential operator in formula (47). It is a tensor operator emerges as ∇ β ∇ α (1/r).…”

Section: Appendix A: Potential Of Electric Dipole Interactionmentioning

confidence: 99%

“…When stability of dipolar Bose and Fermi gases was investigated in Ref. [47]. Solitons in dipolar boson-boson mixtures were described in Ref.…”

Section: Basic Equationsmentioning

confidence: 99%

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Dispersion properties of transverse waves in electrically polarized BECs

Andreev¹,

Kuz'menkov²

2014

J. Phys. B: At. Mol. Opt. Phys.

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Further development of the method of quantum hydrodynamics in application for Bose-Einstein condensates (BECs) is presented. To consider evolution of polarization direction along with particles movement we have developed corresponding set of quantum hydrodynamic equations. It includes equations of the polarization evolution and the polarization current evolution along with the continuity equation and the Euler equation (the momentum balance equation). Dispersion properties of the transverse waves including the electromagnetic waves propagating through the BECs are considered. To this end we consider full set of the Maxwell equations for description of electromagnetic field dynamics. This approximation gives us possibility to consider the electromagnetic waves along with the matter waves. We find a splitting of the electromagnetic wave dispersion on two branches. As a result we have four solutions, two for the electromagnetic waves and two for the matter waves, the last two are the concentration-polarization waves appearing as a generalization of the Bogoliubov mode. We also obtain that if the matter wave propagate perpendicular to external electric field when dipolar contribution does not disappear (as it follows from our generalization of the Bogoliubov spectrum). In this case exist a small dipolar frequency shift due to transverse electric field of perturbation.I.

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OpenMP Fortran and C programs for solving the time-dependent Gross–Pitaevskii equation in an anisotropic trap

Young-S.

Vudragović

Muruganandam

et al. 2016

Computer Physics Communications

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We present new version of previously published Fortran and C programs for solving the Gross-Pitaevskii equation for a Bose-Einstein condensate with contact interaction in one, two and three spatial dimensions in imaginary and real time, yielding both stationary and non-stationary solutions. To reduce the execution time on multicore processors, new versions of parallelized programs are developed using Open Multi-Processing (OpenMP) interface. The input in the previous versions of programs was the mathematical quantity nonlinearity for dimensionless form of Gross-Pitaevskii equation, whereas in the present programs the inputs are quantities of experimental interest, such as, number of atoms, scattering length, oscillator length for the trap, etc. New output files for some integrated one-and two-dimensional densities of experimental interest are given. We also present speedup test results for the new programs. . However, a vast majority of users use single-computer programs, with which the solution of a realistic dynamical 1D problem, not to mention the more complicated 2D and 3D problems, could be time consuming. Now practically all computers have multicore processors, ranging from 2 up to 18 and more CPU cores. Some computers include motherboards with more than one physical CPU, further increasing the possible number of available CPU cores on a single computer to several tens. The present programs are parallelized using OpenMP over all the CPU cores and can significantly reduce the execution time. Furthermore, in the old version of the programs [1, 2] the inputs were based on the mathematical quantity nonlinearity for the dimensionless form of the GP equation. The inputs for the present versions of programs are given in terms of phenomenological variables of experimental interest, as in Refs. [4,5], i.e., number of atoms, scattering length, harmonic oscillator length of the confining trap, etc. Also, the output files are given names which make identification of their contents easier, as in Refs. [4,5]. In addition, new output files for integrated densities of experimental interest are provided, and all programs were thoroughly revised to eliminate redundancies. Summary of revisions: Previous Fortran [1] and C [2] programs for the solution of time-dependent GP equation in 1D, 2D, and 3D with different trap symmetries have been modified to achieve two goals. First, they are parallelized using OpenMP interface to reduce the execution time in multicore processors. Previous C programs [2] had OpenMPparallelized versions of 2D and 3D programs, together with the serial versions, while here all programs are OpenMPparallelized. Secondly, the programs now have input and output files with quantities of phenomenological interest. There are six trap symmetries and both in C and in Fortran there are twelve programs, six for imaginary-time propagation and six for real-time propagation, totaling to 24 programs. In 3D, we consider full radial symmetry, axial symmetry and full anisotropy. In 2D, we consider circular symmet...

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Stability of trapped degenerate dipolar Bose and Fermi gases

Cited by 5 publications

References 51 publications

Dipolar Bose gas in a highly anharmonic trap

Dipolar Bose gas in a highly anharmonic trap

Dispersion properties of transverse waves in electrically polarized BECs

OpenMP Fortran and C programs for solving the time-dependent Gross–Pitaevskii equation in an anisotropic trap

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