共查询到20条相似文献,搜索用时 15 毫秒
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Yu. A. Avetisyan V. A. Malyshev E. D. Trifonov 《Journal of Experimental and Theoretical Physics》2020,130(3):380-386
Photon recoil upon light scattering by a Bose–Einstein condensate (BEC) of a dilute atomic gas is analyzed theoretically accounting for a weak interatomic interaction. Our approach is based on the Gross–Pitaevskii equation for the condensate, which is coupled to the Maxwell equation for the field. The dispersion relations of recoil energy and momentum are calculated, and the effect of weak nonideality of the condensate on the photon recoil is ubraveled. A good agreement between the theory and experiment [7] on the measurement of the photon recoil momentum in a dispersive medium is demonstrated. 相似文献
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Dynamical and Geometric Phases of a Two Energy-Level Bose-Einstein Condensate Interacting with a Laser Field
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By using of the invariant theory, we study a two energy-level Bose-Einstein condensate interacting with a timedependent laser field, the dynamical and geometric phases are given respectively. The Aharonov-Anandan phase is also obtained under the cyclical evolution. 相似文献
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M. R. Setare 《International Journal of Theoretical Physics》2006,45(2):425-435
The Casimir stress on a cylindrical shell in background of conformally flat spacetime for massless scalar field is investigated. In the general case of Robin (mixed) boundary condition, formulae are derived for the vacuum expectation values of the energy–momentum tensor and vacuum forces acting on boundaries. The special case of the dS bulk is considered then different cosmological constants are assumed for the space inside and outside of the shell to have general results applicable to the case of cylindrical domain wall formations in the early universe. 相似文献
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Lenac Z 《Physical review letters》2006,96(21):218901; author reply 218902
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The mechanism of the formation of a surprisingly long suspended liquid bridge subjected to a dc electric field has been intensively studied in the past few decades. However, the role of electrostriction and quantitative evaluation of surface tension in the bridge have not been evaluated. We present combined theoretical and experimental studies on this issue. Electrostriction is pointed out to be the driving force that pushes liquid upward against gravity and into the gap between two containers and forms the suspended bridge, which is within the framework of the Maxwell pressure tensor. Through a comparison between experiment and theory, the surface tension is found to play an important role in holding the long suspended bridge. Ignorance of the surface tension leads to much smaller bridge length than the experimental values. The dynamic stability of the bridge with respect to its diameter, length and conductance is also discussed. 相似文献
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We show that a solitary surface wave can exist at the boundary between a plasma and a dielectric, due to a balance between the nonlinear surface charge terms and the dispersive terms which here are caused by the presence of a high-frequency incident electromagnetic wave. The solitary wave propagation velocity, which depends on the intensity of the incident field, is also calculated. 相似文献
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I. I. Tashlykova-Bushkevich V. G. Shepelevich M. Amati L. Gregoratti M. Kiskinova 《Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques》2020,14(1):66-72
The microstructure and physicochemical properties of the surface of rapidly solidified Al–Cr alloys containing 1 and 3 at % of chromium are studied by means of photoelectron microscopy using synchrotron radiation, scanning probe microscopy, and the sessile-drop technique. We find that the surface oxide-hydroxide layer of foils has a heterogeneous structure with highly dispersed chromium inclusions (possibly clusters). Chromium and aluminum are predominantly in a metallic state in chromium-enriched regions of the foil surface. We find that the equilibrium contact angle of wetting of the samples with water depends on their morphology and the concentration of chromium in the alloys. The wettability is mainly determined by the chemical composition of the surface of foils and to a lesser extent its roughness. A decrease from poor to low water wettability of rapidly solidified Al–Cr alloys with an increase in the chromium concentration up to 3 at % is due to the aggregation of chromium inclusions. 相似文献
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We analyze the problem of phase coexistence, surface tension and the interface patterns between liquid and vapour for the nonlocal free energy functional derived by Lebowitz, Mazel, and Presutti from a system of particles interacting through Kac potentials in the continuum. We study the sharp interface limit in d dimensions and characterize the shape of the interface profiles in the temperature region where a monotonicity property is valid. We further extend our analysis beyond this domain by performing numerical simulations. 相似文献
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We study the canonical quantization of the theory given by Chamseddine–Connes spectral action on a particular finite spectral triple with algebra M2(C)⊕C. We define a quantization of the natural distance associated with this noncommutative space and show that the quantum distance operator has a discrete spectrum. We also show that it would be the same for any other geometric quantity. Finally we propose a physical Hilbert space for the quantum theory. This spectral triple had been previously considered by Rovelli as a toy model, but with a different action which was not gauge invariant. The results are similar in the two cases, but the gauge invariance of the spectral action manifests itself by the presence of a non-trivial degeneracy structure for our distance operator. 相似文献
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We propose a model of phase transformation cubic argentite–monoclinic acanthite in silver sulfide Ag2S (AgS0.5) as ordering in two argentite sublattices. We have determined the channel of the disorder–order transition including four nonequivalent superstructure vectors of stars {k9} and {k4}. For monoclinic acanthite α-Ag2S, we have calculated the distribution function for silver atoms occupying b positions in argentite, as well as the distribution function for sulfur atoms. Ordering in both sublattices is complicated by static atomic displacements. The displacement of S atoms distort the body-centered cubic (bcc) nonmetallic argentite sublattice, forming a monoclinic lattice in which silver atoms are at large distances from one another and occupy their crystallographic positions with unit probability. We have determined the range of admissible values of long-range order parameters η9 and η4 for the model monoclinic ordered α-Ag2S phase. 相似文献
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应用饱和蒸汽压下单元液体的玻尔兹曼因子方程,导出了表面张力系数及其温度变化率的数学公式;依据数学公式定量计算的理论结果与实测值高度吻合;证实了简洁的数学公式,可以在很宽的温度范围内准确地描述表面张力随温度的变化而变化的自然规律. 相似文献
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Maxwell's equations are established for the free electromagnetic field in two-dimensional space-times. In Minkowski space they are solved under the boundary conditions set by a pair of uniformly accelerated plates. With the help of these solutions we determine the regularized energy-momentum tensor of the canonically quantized electromagnetic field at the position of one of the plates. Thereby (as a new result) we arrive at a Casimir effect in an accelerated reference frame.University of New Mexico Albuquerque New Mexico 87131This paper is dedicated to Professor Peter Mittelstaedt, University of Cologne, in honour of his sixtieth birthday.On leave of absence from the NBC Defense Research and Development Institute, D-3042 Munster, P.O.B. 1320, Federal Republic of Germany. 相似文献
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V. A. Atsarkin V. V. Demidov T. A. Shaikhulov 《Journal of Experimental and Theoretical Physics》2020,130(2):228-234
The problem of spin current generation and transformation into electric signals in thin-film ferromagnet/nonmagnetic metal bilayer structures is investigated. This direction is of considerable scientific interest and promising for applications in spintronics. An LSMO/Pt structure consisting of an epitaxial film of ferromagnetic manganite La2/3Sr1/3O3 grown on a single-crystal NdGaO3 substrate and coated with a platinum film has been studied experimentally. The spin current was generated by the spin pumping method upon the excitation of a ferromagnetic resonance in the ferromagnetic layer and was detected by the electric voltage USP arising in the nonmagnetic metal layer due to the inverse spin Hall effect. Owing to its relatively low Curie temperature (~350 K), using LSMO allowed the influence of ferromagnetic-layer magnetization on the spin current generation to be studied in detail in the temperature range 100–350 K. In this case, the influence of the shape of the ferromagnetic resonance line, which is the convolution of homogeneous (Lorentzian) spin packets and inhomogeneous Gaussian broadening (Voigt model), was consistently taken into account. As a result of our analysis of all the parameters defining USP, we have obtained the temperature dependence of the mixed spin conductance, which has turned out to be approximately proportional to the ferromagnet magnetization squared. This result is compared with existing theoretical models. 相似文献
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超Jaynes-cummings模型的热力学性质 总被引:2,自引:0,他引:2
对含有逆场算符的超J-C模型进行了研究,精确得到了超J-C模型哈密顿量的本征值和本征态,求出了系统的超配分函数,最后给出了系统的热力学量,并分别在高温和低温下对系统的热力学性质进行了讨论。 相似文献
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R. F. Buser R. D. Viollier P. Zimak 《International Journal of Theoretical Physics》1988,27(8):925-993
The canonical quantization formalism is applied to the Lagrange density of chromodynamics, which includes gauge fixing and Faddeev-Popov ghost terms in a general covariant gauge. We develop the quantum theory of the interacting fields in the Dirac picture, based on the Gell-Mann and Low theorem and the Dyson expansion of the time evolution operator. The physical states are characterized by their invariance under Becchi-Rouet-Stora transformations. Subsequently, confinement is introduced phenomenologically by imposing, on the quark, gluon, and ghost field operators, the linear boundary conditions of the MIT bag model at the surface of a spherically symmetric and static cavity. Based on this formalism, we calculate, in the Feynman gauge, all nondivergent Feynman diagrams of second order in the strong coupling constantg. Explicit values of the matrix elements are given for low-lying quark and gluon cavity modes. 相似文献
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A. N. Latyshev O. V. Ovchinnikov S. S. Okhotnikov 《Journal of Applied Spectroscopy》2003,70(6):817-820
A method for obtaining the spectra of atoms adsorbed on a single crystal with an ion-covalent bond is suggested. A photostimulated burst of luminescence is used to record the spectra. The atoms are deposited in a vacuum by a mass-spectrometric technique. The absorption spectrum of silver atoms adsorbed on a silver chloride single crystal at concentrations comprising a millionth fraction of the surface monolayer has been obtained. It has been revealed that the optical ionization potential of an adsorbed silver atom is equal to 1.9 eV. 相似文献