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1.
Modulational Instability of Dipolar Bose-Einstein Condensates in Optical Lattices with Three-Body Interactions
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Motivated by the recent experiment [Nature 530(2016) 194] in which a stable droplet in a dipolar quantum gas has been created by the interaction-induced instability, we focus on the modulation instability of an optically-trapped dipolar Bose-Einstein condensate with three-body interaction. Within the mean-field level, we analytically solve the discrete cubic-quintic Gross-Pitaevskii equation with dipole-dipole interaction loaded into a deep optical lattice and show how combined effects of the three-body interaction and dipole-dipole interaction on the condition of modulational instability. Our results show that the interplay of the three-body interaction and dipole-dipole interaction can dramatically change the modulation instability condition compared with the ordinary Gross-Pitaevskii equation. We believe that the predicted results in this work can be useful for the future possible experiment of loading a Bose-Einstein condensate of ~(164)Dy atoms with strong magnetic dipole-dipole interaction into an optical lattice. 相似文献
2.
Dynamical stability of dipolar condensate in a parametrically modulated one-dimensional optical lattice
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《中国物理 B》2021,30(6):60307-060307
We study the stabilization properties of dipolar Bose–Einstein condensate in a deep one-dimensional optical lattice with an additional external parametrically modulated harmonic trap potential. Through both analytical and numerical methods, we solve a dimensionless nonlocal nonlinear discrete Gross–Pitaevskii equation with both the short-range contact interaction and the long-range dipole–dipole interaction. It is shown that, the stability of dipolar condensate in modulated deep optical lattice can be controled by coupled effects of the contact interaction, the dipolar interaction and the external modulation. The system can be stabilized when the dipolar interaction, the contact interaction, the average strength of potential and the ratio of amplitude to frequency of the modulation satisfy a critical condition. In addition, the breather state, the diffused state and the attractive-interaction-induced-trapped state are predicted. The dipolar interaction and the external modulation of the lattice play important roles in stabilizing the condensate. 相似文献
3.
We investigate the structure of trapped Bose-Einstein condensates (BECs) with long-range anisotropic dipolar interactions. We find that a small perturbation in the trapping potential can lead to dramatic changes in the condensate's density profile for sufficiently large dipolar interaction strengths and trap aspect ratios. By employing perturbation theory, we relate these oscillations to a previously identified "rotonlike" mode in dipolar BECs. The same physics is responsible for radial density oscillations in vortex states of dipolar BECs that have been predicted previously. 相似文献
4.
It is shown that strong coupling of Bose–Einstein condensates to an optical cavity can be realized experimentally. With an additional driven microwave field, we show that a highly nonlinear coupling among atoms in a Bose–Einstein condensate can be induced with the assistance of the cavity mode. With such interaction, we can investigate the generation of many body entangled states. In particularly, we show that multipartite entangled GHZ states can be obtained in such architecture with current available techniques. 相似文献
5.
M. Takahashi S. Ghosh T. Mizushima K. Machida 《The European Physical Journal B - Condensed Matter and Complex Systems》2009,68(3):391-400
We show that the effective theory of long wavelength low energy behavior of a dipolar Bose-Einstein condensate(BEC) with large
dipole moments (treated as a classical spin) can be modeled using an extended non-linear sigma model (NLSM) like energy functional
with an additional non-local term that represents long ranged anisotropic dipole-dipole interaction. Minimizing this effective
energy functional we calculate the density and spin-profile of the dipolar Bose-Einstein condensate in the mean-field regime
for various trapping geometries. The resulting configurations show strong intertwining between the spin and mass density of
the condensate, transfer between spin and orbital angular momentum in the form of Einstein-de Hass effect, and novel topological
properties. We have also described the theoretical framework in which the collective excitations around these mean field solutions
can be studied and discuss some examples qualitatively. 相似文献
6.
Griesmaier A Stuhler J Koch T Fattori M Pfau T Giovanazzi S 《Physical review letters》2006,97(25):250402
We have measured the relative strength epsilon dd of the magnetic dipole-dipole interaction compared with the contact interaction in a dipolar chromium Bose-Einstein condensate. We analyze the asymptotic velocities of expansion of the condensate with different orientations of the atomic magnetic moments. By comparing the experimental results with numerical solutions of the hydrodynamic equations for dipolar condensates, we obtain epsilon dd = 0.159+/-0.034. We use this result to determine the s-wave scattering length a = (5.08+/-1.06 x 10(-9)) m = (96+/-20) a0 of 52Cr. This is fully consistent with our previous measurements on the basis of Feshbach resonances and therefore confirms the validity of the theoretical approach used to describe the dipolar Bose-Einstein condensate. 相似文献
7.
We calculate perturbatively the effect of a dipolar interaction upon the Bose-Einstein condensation temperature. This dipolar shift depends on the angle between the symmetry axes of the trap and the aligned atomic dipole moments, and is extremal for parallel or orthogonal orientations, respectively. The difference of both critical temperatures exhibits most clearly the dipole-dipole interaction and can be enhanced by increasing both the number of atoms and the anisotropy of the trap. Applying our results to chromium atoms, which have a large magnetic dipole moment, shows that this dipolar shift of the critical temperature could be measured in the ongoing Stuttgart experiment. 相似文献
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11.
Merging and splitting dynamics between two bright solitons in dipolar Bose-Einstein condensates
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We numerically study the interaction dynamics of two bright solitons with zero initial velocities in the one-dimensional dipolar Bose-Einstein condensates. Under different dipolar strengths, the two bright solitons can merge into a breathing wave, and then split or propagate constantly after several oscillating periods. We quantitatively study the breathing frequency of wave after merging and the asymmetry property of solitons after splitting, and analyze their formation mechanism by the system's energy evolution. Also, the change of initial phase difference brings distinct effects on the soliton interaction. Our results provide insight into the new dynamical phenomena in dipolar systems and enrich the understanding for interaction between dipolar solitons. 相似文献
12.
H. C. Lee T. F. Jiang 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2010,58(3):311-325
We derive the effective Gross-Pitaevskii equation for a slowly rotating
dipolar Bose-Einstein condensate (BEC) with a quantized vortex along a
one-dimensional optical lattice and calculate its band structures. The band
structure of a slowly rotating BEC in a lattice becomes interesting when
dipole-dipole interaction (DDI) is involved. Under rotation, a dipolar
rotating term emerges from the DDI potential. The dipolar rotating term
makes a BEC with an attractive DDI more stable than one with a repulsive
DDI. The dipolar rotating term changes and generalizes the definition for
the type of BEC, which cannot be simply determined by an s-wave scattering
length or an effective contact interaction term. The dipolar rotating term
also makes the band structure fascinating and tunable. A so-called
swallowtail band structure, i.e., a multi-valued solution due to nonlinear
interaction, can either elongate or shrink as the band index increases, in
contrast to a non-rotating dipolar BEC system with a monotonic dependence.
With the dipolar rotating term, various band structures as well as an
attractive BEC without collapse can be easily achieved. We demonstrate that
a rotating dipolar BEC system subject to an optical lattice combines
features of a crystal and a superfluid and promises wide applications. 相似文献
13.
利用线性稳定性分析的方法,对光晶格中双组分偶极玻色-爱因斯坦凝聚体(Bose-Einstein condensates,简称BECs)的调制不稳定性进行了研究.得到了光晶格中双组分偶极BECs原子系统调制不稳定性区域的分布与在位相互作用和由偶极-偶极相互作用所导致的格点间BECs相互作用之间的关系.结果显示,格点间BECs的相互作用对光晶格中双组分偶极BECs的调制不稳定性有较大的影响,这可为实际应用中如何操控双组分偶极BECs提供有用的信息.
关键词:
光晶格
双组分玻色-爱因斯坦凝聚体
调制不稳定性
偶极-偶极相互作用 相似文献
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Al-Hashimi HM Valafar H Terrell M Zartler ER Eidsness MK Prestegard JH 《Journal of magnetic resonance (San Diego, Calif. : 1997)》2000,143(2):402-406
Residual dipolar couplings for pairs of proximate magnetic nuclei in macromolecules can easily be measured using high-resolution NMR methods when the molecules are dissolved in dilute liquid crystalline media. The resulting couplings can in principle be used to constrain the relative orientation of molecular fragments in macromolecular systems to build a complete structure. However, determination of relative fragment orientations based on a single set of residual dipolar couplings is inherently hindered by the multi-valued nature of the angular dependence of the dipolar interaction. Even with unlimited dipolar data, this gives rise to a fourfold degeneracy in fragment orientations. In this Communication, we demonstrate a procedure based on an order tensor analysis that completely removes this degeneracy by combining residual dipolar coupling measurements from two alignment media. Application is demonstrated on (15)N-(1)H residual dipolar coupling data acquired on the protein zinc rubredoxin from Clostridium pasteurianum dissolved in two different bicelle media. 相似文献
16.
We investigate the effective interaction between two heavy impurities immersed in a quasi-twodimensional dipolar Bose-Einstein condensate via a variation approach. We show that the mediated interaction is highly tunable via the contact and the dipole-dipole interactions between the background gas atoms. Interestingly, the mediated interaction potential may become an oscillating function of inter-impurity distance when roton excitation emerges under sufficiently strong dipolar interaction. Our system therefore provides an efficient way for tuning the mediated interaction between impurities. 相似文献
17.
《Journal of magnetism and magnetic materials》1995,149(3):L246-L250
We present a comparison of the strength of the classical dipolar interaction, relative to quantum-mechanical coupling mechanisms like RKKY and complete confinement, between two ferromagnetic films separated by a paramagnetic spacer. The classical dipolar coupling, which vanishes if the two interfaces are perfectly continuous and flat, builds up strength as the interface roughness grows for several models of interface topography. These numerical estimates, carried out for a Co/Cu/Co trilayer show that, in the presence of substantial surface roughness, the dipole-dipole interaction strength is comparable, and at times even larger, than those obtained using other well established mechanisms. These results are also in qualitative agreement with experimental measurements in a variety of multilayer systems. Thus, for rough interfaces, the dipolar interaction cannot be ignored. 相似文献
18.
The analysis of the polariton modes in 2D traps based on heterostructures with quantum wells for Bose-Einstein condensation
of dipolar excitons is presented. The characteristic equation of such modes is derived with allowance for the polarization
relaxation of excitons and radiative losses from the trap. The spectrum and structure of high-quality modes are analytically
and numerically studied. It is demonstrated that several modes become unstable at a high enough density of excitons and a
long relaxation time of the exciton polarization. In accordance with the estimations, such an instability can be reached in
the experiments on the Bose-Einstein condensation of dipolar excitons and can be used to interpret the corresponding coherent
emission. 相似文献
19.
The spin dynamics of atomic Bose-Einstein condensates confined in a one-dimensional optical lattice is studied. The condensates at each lattice site behave like spin magnets that can interact with each other through both the light-induced dipole-dipole interaction and the static magnetic dipole-dipole interaction. We show how these site-to-site dipolar interactions can distort the ground-state spin orientations and lead to the excitation of spin waves. The dispersion relation of the spin waves is studied and possible detection schemes are proposed. 相似文献
20.
Spinor F=1 Bose–Einstein condensates loaded in two types of radially-periodic potentials with spin–orbit coupling
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《中国物理 B》2021,30(10):106701-106701
We consider two-dimensional spinor F = 1 Bose–Einstein condensates in two types of radially-periodic potentials with spin–orbit coupling, i.e., spin-independent and spin-dependent radially-periodic potentials. For the Bose–Einstein condensates in a spin-independent radially-periodic potential, the density of each component exhibits the periodic density modulation along the azimuthal direction, which realizes the necklacelike state in the ferromagnetic Bose–Einstein condensates. As the spin-exchange interaction increases, the necklacelike state gradually transition to the plane wave phase for the antiferromagnetic Bose–Einstein condensates with larger spin–orbit coupling. The competition of the spin-dependent radially-periodic potential, spin–orbit coupling, and spin-exchange interaction gives rise to the exotic ground-state phases when the Bose–Einstein condensates in a spin-dependent radially-periodic potential. 相似文献