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981.
Josephson oscillation of a superfluid Fermi gas 总被引:1,自引:0,他引:1
S. K. Adhikari 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2008,47(3):413-419
Using the complete numerical solution of a time-dependent
three-dimensional mean-field model we
study the Josephson oscillation of a superfluid Fermi gas (SFG) at zero temperature formed in a combined axially-symmetric
harmonic plus one-dimensional periodic optical-lattice (OL) potentials after displacing the harmonic trap along the axial
OL
axis. We study the dependence of Josephson frequency on the strength of the OL potential. The Josephson frequency decreases
with increasing strength as found in the experiment of Cataliotti et al. [Science 293, 843 (2001)] for a Bose-Einstein condensate and of the experiment of Pezzè et al. [Phys. Rev. Lett. 93, 120401 (2004)] for an ideal Fermi gas. We demonstrate a
breakdown of Josephson oscillation in the SFG for a large displacement
of the harmonic trap. These features of Josephson oscillation of a SFG can be tested experimentally. 相似文献
982.
Dariush Souri Mohammad Elahi Mohammad S. Yazdanpanah 《Central European Journal of Physics》2008,6(2):306-310
The ternary 70P2O5-10Li2MoO4-20Li2O and 70P2O5-10Na2MoO4-20Na2O glasses, prepared by the press-melt quenching technique, were studied at temperatures between 298 and 418 K for their high
dc electric field properties. For the above purpose, the effect of a strong electric field on the dc conduction of these amorphous
bulk samples was investigated using the gap-type electrode configuration. At low electric fields, the current-voltage (I — V) characteristics have a linear shape, while at high electric fields (> 103 V/cm), bulk samples show nonlinear effects (nonohmic conduction). Current-voltage curves show increasing departure from Ohm’s
law with increasing current density, leading to critical phenomena at a maximum voltage (threshold voltage), known as switching
(switch from a low-conduction state to a higher-conduction state at threshold voltage). The Pool-Frenkel high-field effect
was observed at electrical fields of about 103–104 V/cm; then the lowering factor of the potential barrier, the high frequency dielectric constant, and the refractive index
of these glasses were determined.
相似文献
983.
Higher-order effects on self-similar parabolic pulse in the microstructured fibre amplifier
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By considering higher-order effects, the properties of self-similar parabolic pulses propagating in the microstructured fibre amplifier with a normal group-velocity dispersion have been investigated. The numerical results indicate that the higher-order effects can badly distort self-similar parabolic pulse shape and optical spectrum, and at the same time the peak shift and oscillation appear, while the pulse still reveals highly linear chirp but grows into asymmetry. The influence of different higher-order effects on self-similar parabolic pulse propagation has been analysed. It shows that the self-steepening plays a more important role. We can manipulate the geometrical parameters of the microstructured fibre amplifier to gain a suitable dispersion and nonlinearity coefficient which will keep high-quality self-similar parabolic pulse propagation. These results are significant for the further study of self-similar parabolic pulse propagation. 相似文献
984.
By using star product method, the He-McKellar-Wilkens (HMW) effect for spin-one neutral particle on noncommutative (NC) space is studied. After solving the Kemmer-like equations on NC space, we obtain the topological HMW phase on NC space where the additional terms related to the space-space non-commutativity are given explicitly. 相似文献
985.
The magnetization reversal of Fe/Cu(100) ultrathin films grown at
room temperature is investigated by using an in situ
magneto-optical Kerr effect polarimeter with a magnet that can
rotate in a plane of incidence. There occur spin reorientation
transitions from out-of-plane to in-plane magnetizations in 8 and 12
monolayers (ML) thick iron films. The coercive fields are observed
to be proportional to the reciprocal of the cosine with respect to
the easy axis, suggesting that the domain-wall displacement plays a
main role in the magnetization reversal process. 相似文献
986.
A. B. Bhattacherjee 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2008,46(3):499-506
We study the effect of a one dimensional optical superlattice on the superfluid properties (superfluid fraction, number squeezing,
dynamic structure factor) and the quasi-momentum distribution of the Mott-insulator. We show that due to the secondary lattice,
there is a decrease in the superfluid fraction and the number fluctuation. The dynamic structure factor which can be measured
by Bragg spectroscopy is also suppressed due to the addition of the secondary lattice. The visibility of the interference
pattern (the quasi-momentum distribution) of the Mott-insulator is found to decrease due to the presence of the secondary
lattice. Our results have important implications in atom interferometry and quantum computation in optical lattices. 相似文献
987.
Temperature effect on dissipative holographicscreening-photovoltaic solitons in a biased dissipative system
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In a biased dissipative photovoltaic-photorefractive system, this paper investigates the temperature effect on the evolution and the self-deflection of the dissipative holographic screening-photovoltaic (DHSP) solitons. The results reveal that, the evolution and the self-deflection of the bright and dark DHSP solitons are influenced by the system temperature. At a given temperature, for a stable DHSP soliton originally formed in the dissipative system, it attempts to evolve into another DHSP soliton when the temperature change is appropriately small, whereas it will become unstable or break down if the temperature departure is large enough. Moreover, the self-deflection degree of the solitary beam centre increases as temperature rises in some range, while it is decided by the system parameters and is slight under small-signal condition. The system temperature can be adjusted to change the formation and the self-deflection of the solitary beam in order to gain certain optical ends. In a word, the system temperature plays a role for the DHSP solitons in the dissipative system. 相似文献
988.
Multiferroic NiFe2O4 (NFO)-BaTiO3 (BTO) bilayered thin films are epitaxially grown on (001) Nb-doped SrTiO3 (STO) substrates by pulsed-laser deposition (PLD). Different growth sequences of NFO and BTO on the substrate yield two kinds of epitaxial heterostructures with (001)-orientation, i.e. (001)-NFO/(001)-BTO/substrate and (001)- BTO/(001)-NFO/substrate. Microstructure studies from x-ray diffraction (XRD) and electron microscopies show differences between these two heterostructures, which result in different multiferroic behaviours. The heterostructured composite films exhibit good coexistence of both ferroelectric and ferromagnetic properties, in particular, obvious magnetoelectric (ME) effect on coupling response. 相似文献
989.
通过对坐标系统进行旋转,计算得到了三次型波前编码系统的倾斜入射的光瞳函数,并给出了近似表达式. 分析表明倾斜入射会产生三次相位扩大效应和离焦扩大效应,它们和入射角的正负无关,且随着入射角绝对值的增大而增大. 这表现在点扩散函数(point spread function, PSF)上会扩展PSF包络的两条直角边,表现在调制传递函数(modulation transfer function, MTF)上会降低MTF值. 子午面倾斜入射时,子午方向的三次相位扩大效应和离焦放大效应大于弧矢方向,从而导致子午方向 相似文献
990.
从实验上证实Hg0.695Cd0.305Te 光电二极管空间电荷区中存在双光子吸收的Franz-Keldysh效应.利用一个皮秒Nd:YAG激光器抽运的光学参量产生器和差频产生器作为激发光源,测量了入射波长为λ0=7.92μm的脉冲激光所激发的光响应随入射光强的变化关系.脉冲光响应峰值强度随入射光强的增大呈现二次幂函数增强趋势.采用等效RC电路模型将脉冲光伏信号峰值与入射光强相关联,得到空间电荷区中强电场下单光束 相似文献