共查询到20条相似文献,搜索用时 10 毫秒
1.
提出了一种处理玻色-爱因斯坦凝聚啁啾孤子动力学的拓展变分方法,深入研究了玻色-爱因斯坦凝聚孤子在周期势与抛物势联合作用下的动力学演化,利用拓展变分法给出了解析处理,并和基于分步傅里叶变换的直接数值法进行比较,发现这种拓展变分方法能够充分揭示上述外势场中的玻色-爱因斯坦凝聚啁啾孤子的动力学行为和特征.同时给出了能支持多稳定晶格囚禁玻色-爱因斯坦凝聚啁啾孤子的周期势与抛物势强度比值的临界值和一种通过控制外势场可有选择地移动玻色-爱因斯坦凝聚啁啾孤子的操控方法,这为玻色-爱因斯坦凝聚的实验和应用研究提供了理论参
关键词:
玻色-爱因斯坦凝聚
Gross-Pitaevskii方程
啁啾孤子
操控 相似文献
2.
It is demonstrated that Smale-horseshoe chaos exists in the time evolution of the one-dimensional Bose-Einstein condensate driven by time-periodic harmonic or inverted-harmonic potential.A formally exact solution of the time-dependent Gross-Pitaevskii equation is constructed,which describes the matter shock waves with chaotic or periodic amplitudes and phases. 相似文献
3.
4.
Fuzhong Cong Zhixia Wang Hongtu Hua Shichun Pang Shouyu Tong 《Journal of Experimental and Theoretical Physics》2012,114(3):377-381
The spatial structure of the Bose-Einstein condensate (BEC) is investigated and spatially chaotic distributions of the condensates
are revealed. By means of changing the s-wave scattering length with a Feshbach resonance, the chaotic behavior can be well controlled to enter into periodicity.
Numerical simulation shows that there are different periodic orbits according to different s-wave scattering lengths only if the Lyapunov exponent of the system is negative. 相似文献
5.
P. A. Andreev 《Russian Physics Journal》2012,54(12):1360-1363
6.
An optical speckle potential is used to investigate the static and dynamic properties of a Bose-Einstein condensate in the presence of disorder. With small levels of disorder, stripes are observed in the expanded density profile and strong damping of dipole and quadrupole oscillations is seen. Uncorrelated frequency shifts of the two modes are measured and are explained using a sum-rules approach and by the numerical solution of the Gross-Pitaevskii equation. 相似文献
7.
We show that even in three dimensions an antiferromagnetic spin-1 Bose-Einstein condensate, which can, for instance, be created with (23)Na atoms in an optical trap, has not only singular linelike vortex excitations, but also allows for singular pointlike topological excitations, i.e., monopoles similar to the 't Hooft-Polyakov monopoles. We discuss the static and dynamic properties of these monopoles. 相似文献
8.
针对近零温度下玻色-爱因斯坦凝聚态的特点,建立了复合原子表示模型.提出了复合原子的概念,研究发现复合原子具有一定的零点半径与结合能,得出了相应的表达式.认为该物态作为一个宏观量子态的说法具有相对性,应该据研究角度而定.同时,给出了二个分离的玻色-爱因斯坦凝聚态之间产生1/R型作用势的几种情况,为同类实验提供了理论依据. 相似文献
9.
We show that knots of spin textures can be created in the polar phase of a spin-1 Bose-Einstein condensate, and discuss experimental schemes for their generation and probe, together with their lifetime. 相似文献
10.
Presented is a type-II quantum algorithm for superfluid dynamics, used to numerically predict solutions of the GP equation
for a complex scalar field (spinless bosons) in φ4 theory. The GP equation is a long wavelength effective field theory of a microscopic quantum lattice gas with nonlinear state
reduction. The quantum lattice gas algorithm for modeling the dynamics of the one-body BEC state in 3+1 dimensions is presented.
To demonstrate the method's strength as a computational physics tool, a difficult situation of filamentary singularities is
simulated, the dynamics of solitary vortex-antivortex pairs, which are a basic building block of morphologies of quantum turbulence. 相似文献
11.
An essentially exact approach to compute the wave function in the time-dependent many-boson Schr?dinger equation is derived and employed to study accurately the process of splitting a trapped condensate. As the trap transforms from a single to double well the ground state changes from a coherent to a fragmented state. We follow the role played by many-body excited states during the splitting process. Among others, a "counterintuitive" regime is found in which the evolution of the condensate when the splitting is sufficiently slow is not to the fragmented ground state, but to a low-lying excited state which is a coherent state. Experimental implications are discussed. 相似文献
12.
从平均场理论出发,针对有限温度下的玻色-爱因斯坦凝聚态的特点,从正则系综的自由能函数变化的角度,推演并得出了临界温度移动的表达式。为同类实验提供了理论依据. 相似文献
13.
McKenzie C Hecker Denschlag J Häffner H Browaeys A de Araujo LE Fatemi FK Jones KM Simsarian JE Cho D Simoni A Tiesinga E Julienne PS Helmerson K Lett PD Rolston SL Phillips WD 《Physical review letters》2002,88(12):120403
We form ultracold Na2 molecules by single-photon photoassociation of a Bose-Einstein condensate, measuring the photoassociation rate, linewidth, and light shift of the J = 1, v = 135 vibrational level of the A1 Sigma (+)(u) molecular state. The photoassociation rate constant increases linearly with intensity, even where it is predicted that many-body effects might limit the rate. Our observations are in good agreement with a two-body theory having no free parameters. 相似文献
14.
We report a measurement of the excitation spectrum omega(k) and the static structure factor S(k) of a Bose-Einstein condensate. The excitation spectrum displays a linear phonon regime, as well as a parabolic single-particle regime. The linear regime provides an upper limit for the superfluid critical velocity, by the Landau criterion. The excitation spectrum agrees well with the Bogoliubov spectrum in the local density approximation, even close to the long-wavelength limit of the region of applicability. Feynman's relation between omega(k) and S(k) is verified, within an overall constant. 相似文献
15.
Roberts JL Claussen NR Cornish SL Donley EA Cornell EA Wieman CE 《Physical review letters》2001,86(19):4211-4214
The point of instability of a Bose-Einstein condensate (BEC) due to attractive interactions was studied. Stable 85Rb BECs were created and then caused to collapse by slowly changing the atom-atom interaction from repulsive to attractive using a Feshbach resonance. At a critical value, an abrupt transition was observed in which atoms were ejected from the condensate. By measuring the onset of this transition as a function of number and attractive interaction strength, we determined the stability condition to be N(absolute value of a) / a(ho) = 0.459+/-0.012+/-0.054, slightly lower than the predicted value of 0.574. 相似文献
16.
We show that elastic collisions between atoms in a Bose-Einstein condensate with attractive interactions can lead to an explosion that ejects a large fraction of the collapsing condensate. We study variationally the dynamics of this explosion and find excellent agreement with recent experiments on magnetically trapped 85Rb. We also determine the energy and angular distribution of the ejected atoms during the collapse. 相似文献
17.
We report the Bose-Einstein condensation (BEC) of the most magnetic element, dysprosium. The Dy BEC is the first for an open f-shell lanthanide (rare-earth) element and is produced via forced evaporation in a crossed optical dipole trap loaded by an unusual, blue-detuned and spin-polarized narrowline magneto-optical trap. Nearly pure condensates of 1.5 × 10(4) (164)Dy atoms form below T = 30 nK. We observe that stable BEC formation depends on the relative angle of a small polarizing magnetic field to the axis of the oblate trap, a property of trapped condensates only expected in the strongly dipolar regime. This regime was heretofore only attainable in Cr BECs via a Feshbach resonance accessed at a high-magnetic field. 相似文献
18.
Fast rotation of a Bose-Einstein condensate 总被引:1,自引:0,他引:1
We study the rotation of a 87Rb Bose-Einstein condensate confined in a quadratic plus quartic potential. This trap configuration allows one to increase the rotation frequency of the gas above the trap frequency. In such a fast rotation regime we observe a dramatic change in the appearance of the quantum gas. The vortices which were easily detectable for a slower rotation become much less visible, and their surface density is well below the value expected for this rotation frequency domain. We discuss some possible tracks to account for this effect. 相似文献
19.
在周期性脉冲撞击的两分量玻色-爱因斯坦凝聚系统中研究了自旋压缩动力学性质,结果表明:原子自旋压缩动力学能够揭示相空间的混沌和规则结构,即当初始相干态处在混沌区域时,自旋压缩在很短时间后消失,而当初始相干态处在规则区域时,自旋压缩则存在很长时间.特别是随着时间的演化,系统的平均自旋方向的分布和摆动也与初态所处的空间结构有着密切的联系.最后,研究了相空间的整体自旋压缩动力学,得到了一种较好的量子-经典对应.
关键词:
玻色-爱因斯坦凝聚
混沌
自旋压缩
平均自旋方向 相似文献
20.
We describe a wave function engineering approach to the formation of textures in nonrotated multicomponent Bose-Einstein condensates. With numerical simulations of a viable two-component condensate experiment, we demonstrate the formation of a ballistically?expanding regular lattice?texture, composed of half-quantum vortices and spin-2 textures. The formation is described by a linear interference process in which the geometry and phase of three initially separated wave packets provide deterministic control over the resulting lattice?texture. 相似文献