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1.
It is shown that the ground state of deformed nuclei can be considered as a condensate of bosons that do not have a well-defined angular momentum. Values for the quadrupole moment and the particle number that are very close to the values obtained using the full boson wave function are obtained by retaining only the s- and d-parts of the boson wave function.By comparing with the many-shell (realistic) situation we found the limitations of the single-shell calculations. 相似文献
2.
Effects of transverse trapping on the ground state of a cigar-shaped two-component Bose-Einstein condensate 下载免费PDF全文
We derive the coupled nonpolynomial nonlinear Schro¨dinger equations for a two-component Bose-Einstein condensate in a quasi-one-dimension geometry and investigate the effects of a tightly transverse trapping on the ground state and the miscibility-immiscibility threshold. We find that the density profile of the matter wavepacket is remarkably dependent on the transverse width and the effective one-dimension nonlinear coupling strengths in miscible and immiscible regimes. 相似文献
3.
Ticknor C 《Physical review letters》2008,100(13):133202
We explore the impact of the short-range interaction on the scattering of ground state polar molecules and study the transition from a weak to strong dipolar scattering over an experimentally reasonable range of energies and electric field values. In the strong dipolar limit, the scattering scales with respect to a dimensionless quantity defined by mass, induced dipole moment, and collision energy. The scaling has implications for all quantum mechanical dipolar scattering. Furthermore the universal scattering regime will readily be achieved with polar molecules at ultracold temperatures. 相似文献
4.
Deiglmayr J Grochola A Repp M Mörtlbauer K Glück C Lange J Dulieu O Wester R Weidemüller M 《Physical review letters》2008,101(13):133004
Ultracold LiCs molecules in the absolute ground state X1Sigma+, v' = 0, J' = 0 are formed via a single photoassociation step starting from laser-cooled atoms. The selective production of v' = 0, J' = 2 molecules with a 50-fold higher rate is also demonstrated. The rotational and vibrational state of the ground state molecules is determined in a setup combining depletion spectroscopy with resonant-enhanced multiphoton ionization time-of-flight spectroscopy. Using the determined production rate of up to 5 x 10(3) molecules/s, we describe a simple scheme which can provide large samples of externally and internally cold dipolar molecules. 相似文献
5.
《Physics letters. A》2020,384(5):126126
The ground state and the tunnelling dynamics of the Bose-Einstein condensate (BEC) loaded in a tilted shallow trap is studied analytically and numerically. The stable bound state, the quasi-bound state and the diffusion state are predicted. The thresholds for transition between the different states are obtained and the stability diagram in parameter space is presented. The tunnelling dynamics of the system in different states is revealed. The shape of the potential well and the atomic interaction play important role and have coupled effect on the tunnelling dynamics of the system. Furthermore, the resonant tunnelling phenomenon in the parametrically modulated shallow trap is observed. The results show that when the modulating frequency approaches the dipolar mode of the system, resonant tunnelling occurs and the whole system is unstable. Our results provide a theoretical evidence for studying the tunnelling dynamics of the ultracold atomic system. 相似文献
6.
We develop a variational theory for a dipolar condensate in an elongated(cigar shaped)confinement potential. Our formulation provides an effective one-dimensional extended meanfield theory for the ground state and its collective excitations. We apply our theory to investigate the properties of rotons in the system comparing the variational treatment to a full numerical solution. We consider the effect of quantum fluctuations on the scattering length at which the roton excitation softens to zero energy. 相似文献
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Jun Rui 《中国科学:物理学 力学 天文学(英文版)》2023,(11):239-240
<正>Ultracold polar molecules have emerged as a new research frontier in quantum physics and chemistry [1]. These molecules exhibit rich internal rotational, vibrational, and electronic levels, providing new resources for quantum control and quantum metrology. The intrinsic permanent electric dipole moment of polar molecules enables the strong longrange and anisotropic dipole-dipole interaction between spatially displaced molecules and constitutes a valuable tool for simulating novel long-r... 相似文献
9.
G. E. Volovik 《JETP Letters》1997,65(6):491-496
In d-wave superconductors the electronic entropy associated with an isolated vortex diverges logarithmically with the size of
the system even at low temperatures. In the vortex array the entropy per vortex per layer, S
V
, is much larger than k
B
and depends on the distribution of the velocity field v
s
around the vortex. If there is a first-order transition upon a change of the velocity distribution, then there will be a
big entropy jump ΔS
V
∼k
B
at the transition. This entropy jump comes from the electronic degrees of freedom on the vortex background, which is modified
by the vortex transition. This can explain the big jump in the entropy observed in the so-called vortex-melting transition
[A. Junod, M. Roulin, J-Y. Genoud et al., Physica C, to be published], in which the vortex array and thus the velocity field are redistributed. The possibility of
the Berezinskii-Kosterlitz-Thouless transition in the 3-dimensional d-wave superconductor due to the fermionic bound states in the vortex background is discussed.
Pis’ma Zh. éksp. Teor. Fiz. 65, No. 6, 465–469 (25 March 1997)
Published in English in the original Russian journal. Edited by Steve Torstveit. 相似文献
10.
We consider a rotating Bose-Einstein condensate in an optical lattice in the regime in which the system Hamiltonian can be mapped onto a Josephson junction array. In an approximate scheme where the couplings are assumed uniform, the ground state energy is formulated in terms of the vortex configuration. Application of the method for the ladder case presented and the results are compared with Monte-Carlo method. 相似文献
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Photoassociation rates of mixed cold alkali atom pairs and formation rates of cold heteronuclear alkali dimers in their ground state are computed within an approach where the wave functions are calculated exactly, and the laser field is treated as a perturbation. These rates are predicted to have the same magnitude for all heteronuclear species involving either Rb or Cs atoms. Moreover, these rates are found slightly smaller than, or similar to, the same rates for Cs2 molecules, which is encouraging for future experiments. We studied the specific case of the photoassociation into excited molecular states coupled with spin-orbit interaction, emphasizing the role of the so-called resonant coupling in the formation of stable ultracold molecules with low vibrational levels. The comparison with recent experimental results on RbCs photoassociation and cold molecule formation show their reasonable agreement with our calculations.Received: 2 July 2004, Published online: 23 November 2004PACS:
32.80.Pj Optical cooling of atoms; trapping - 33.20.Tp Vibrational analysis - 33.70.Ca Oscillator and band strengths, lifetimes, transition moments, and Franck-Condon factors 相似文献
13.
Time-reversal symmetry breaking by a (d+id) density-wave state in underdoped cuprate superconductors
It was proposed that the id(x(2)-y(2)) density-wave state (DDW) may be responsible for the pseudogap behavior in the underdoped cuprates. Here we show that the admixture of a small d(xy) component to the DDW state breaks the symmetry between the counterpropagating orbital currents of the DDW state and, thus, violates the macroscopic time-reversal symmetry. This symmetry breaking results in a nonzero polar Kerr effect, which has recently been observed in the pseudogap phase. 相似文献
14.
M. Lavagnini F. Pfuner R. Monnier L. Degiorgi H.-M. Eiter L. Tassini B. Muschler R. Hackl J.-H. Chu N. Ru K.Y. Shin I.R. Fisher 《Physica B: Condensed Matter》2012,407(11):1864-1867
We summarize our recent efforts in investigating the charge–density-wave (CDW) state of the rare-earth tri-tellurides RTe3 by means of infrared and Raman techniques. We identify the CDW gap, as order parameter of the broken-symmetry ground state, as well as the collective mode of the CDW condensate. 相似文献
15.
We introduce a new confining potential which simulates preferably the realistic near-harmonic trap for a quasi-one-dimensional (1D) Bose-Einstein condensate (BEC). An exact transmission state of the BEC system is found and the corresponding spatial configurations, metastability, superfluidity and the transport properties are analyzed. Resonant transmission through the potential is predicted from the exact solution. 相似文献
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17.
W.P Su 《Solid State Communications》1982,42(7):497-499
Comuptations of the ground state wave function of a finite polyacetylene ring are carried out using the Monte Carlo method. The qualitative features of the classical solution of the phonon field are shown to survive the quantum fluctuations. 相似文献
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Under certain conditions, the Bose-Einstein condensate confined in a two-dimensional harmonic trap is associated with a one-dimensional nonlinear Schrödinger equation and a soliton solution. The influence of the initial condition on the solution is discussed. The critical initial number of condensed atoms to maintain a soliton is evaluated. In the
Li case, this number is of the order of thousand. The energy per particle of the solitons is also calculated. 相似文献