Geometrical Potential in Giant Fullerenes

Technical Physics - The motion of electrons in giant fullerenes due to geometrical potential is investigated in the one-electron approximation. It is shown that because of flexural excitation of...     

Hubble Expansion Parameter in a New Model of Dark Energy

In this study, we consider new model of dark energy based on Taylor expansion of its density and calculate the Hubble expansion parameter for various parameterizations of equation of state. This model is useful to probe a possible evolving of dark energy component in comparison with current observational data.     

圆极化变参数摇摆器中电子的稳定性研究

采用圆极化变参数摇摆器能延缓自由电子激光器件进入饱和,提高束波互作用效率。通过计算电子运动的柯尔莫哥洛夫熵来研究变参数摇摆器自由电子运动的稳定性。研究结果表明:摇摆器无论采用正坡度还是负坡度,平衡态电子的柯尔莫哥洛夫熵值均小于零,稳定性均比无坡度时好,但电子的运动轨迹趋于发散;当有激光场存在时,正坡度破坏电子运动的稳定性,负坡度改善电子运动的稳定性。其结果为电子运动稳定性的进一步研究提供参考。     

Uniqueness of Bounded Solutions for the Homogeneous Landau Equation with a Coulomb Potential

We prove the uniqueness of bounded solutions for the spatially homogeneous Fokker-Planck-Landau equation with a Coulomb potential. Since the local (in time) existence of such solutions has been proved by Arsen’ev–Peskov (Z. Vycisl. Mat. i Mat. Fiz. 17:1063–1068, 1977), we deduce a local well-posedness result. The stability with respect to the initial condition is also checked.     

螺绕环的电感

给出了螺绕环电感的准确表达式,并对常见问题作了详细的讨论.     

Homogeneous Linewidth and Saturation Parameter of Infrared Laser Transitions

We investigated the behavior of infrared (IR) absorption laser transitions of methanol isotopes in the presence of an uniform electric field, in order to determine Doppler-free spectroscopic data such as homogeneous linewidth and saturation parameter. For this we combine photoacoustic detection with the high resolution provided by the Nonlinear Hanle Effect (NLHE) on molecular transitions.     

Klein Paradox of Two-Dimensional Dirac Electrons in Circular Well Potential

We study two-dimensional massive Dirac equation in circular well potential. The energies of bound states are obtained. We demonstrate the Klein paradox of this relativistic wave equation:For large enough potential depth, the bound states disappear from the spectra. Applications to graphene systems are discussed.     

Droplets of the Order Parameter in a Low Density Attracting Electron System in the Presence of a Strong Random Potential

Journal of Experimental and Theoretical Physics - The properties of a two-dimensional low density (n ? 1) electron system with strong onsite Hubbard attraction U > W (W is the...     

Hopping Parameter Expansion Technique in Noise Method for Disconnected Quark Loops

We investigate the effectiveness of the hopping parameter expansion(HPE) combined with the Z(2) noise method in the calculation of the trace of the inverse of Wilson's Dirac operator and some other disconnected contributions.A numerical comparison of the standard deviation for the Z(2) noise method and HPE with the Z(2) noise method is carried out. It is found that there are noise reductions in all the quantities we calculated using the HPE with the Z(2) noise method. For the trace of the inverse of Wilson's Dirac operator, the HPE can reduce the statistical error by about 60%.     

Abelian Extensions of the Group of Diffeomorphisms of a Torus

In this Letter we construct Abelian extensions of the group of diffecomorphisms of a torus. We consider the Jacobian map, which is a crossed homomorphism from the group of diffeomorphisms into a toroidal gauge group. A pull-back under this map of an invariant central 2-cocycle on a gauge group turns out to be an Abelian cocycle on the group of diffeomorphisms. In the case of a circle we get an interpretation of the Virasoro–Bott cocycle as a pull-back of the Heisenberg cocycle. We also give an Abelian generalization of the Virasoro–Bott cocycle to the case of a manifold with a volume form.     

Perturbation Expansion of Potential of Charged Dielectric Sphere in Asymmetrical Electrolytes

A perturbation expansion for the electrostatic potential of a uniformly charged, dielectric sphere is extended to include asymmetrical electrolytes in the large radius limit. The potential, valid for q?/?T > 1 and small ?D/a near the sphere, is solved in a similar manner to that for 1-1 electrolytes.     

Geometrical Optics in a Rotating Dielectric

Optics and Spectroscopy - A rotating solid homogeneous isotropic dispersion-free dielectric in an accompanying frame of reference turns out to be an inhomogeneous anisotropic medium due to the...     

Robertson-Walker Fluid Sources Endowed with Rotation Characterised by Quadratic Terms in Angular Velocity Parameter

Einstein's equations for a Robertson-Walker fluid source endowed with rotation are presented up to and including quadratic terms in angular velocity parameter. A family of analytic solutions are obtained for the case in which the source angular velocity is purely time-dependent. A subclass of solutions is presented which merge smoothly to homogeneous rotating and non-rotating central sources. The particular solution for dust endowed with rotation is presented. In all cases explicit expressions, depending sinusoidally on polar angle, are given for the density and internal supporting pressure of the rotating source. In addition to the non-zero axial velocity of the fluid particles it is shown that there is also a radial component of velocity which vanishes only at the poles. The velocity four-vector has a zero component between poles.     

Charmonium States in QCD-Inspired Quark Potential Model Using Gaussian Expansion Method

We investigate the mass spectrum and electromagnetic processes of charmonium system with the nonperturbative treatment for the spin-dependent potentials, comparing the pure scalar and scalar-vector mixing linear confining potentials. It is revealed that the scalar-vector mixing confinement would be important for reproducing the mass spectrum and decay widths, and therein the vector component is predicted to be around 22?%. With the state wave functions obtained via the full-potential Hamiltonian, the long-standing discrepancy in M1 radiative transitions of J/ψ and ψ′ are alleviated. This work also provides an inspection and suggestion for the possible cc? states among the copious higher charmonium-like states. Particularly, the newly observed X(4160) and X(4350) are found in the charmonium family mass spectrum as M(2¹ D ₂)?= 4164.9 MeV and M(3³ P ₂)?= 4352.4 MeV, which strongly favor the J ^PC ?=?2^?+, 2⁺⁺ assignments respectively. The corresponding radiative transitions, leptonic and two-photon decay widths have been also predicted theoretically for the further experimental search.     

Statistics of Wave Functions for a Point Scatterer on the Torus

Quantum systems whose classical counterpart have ergodic dynamics are quantum ergodic in the sense that almost all eigenstates are uniformly distributed in phase space. In contrast, when the classical dynamics is integrable, there is concentration of eigenfunctions on invariant structures in phase space. In this paper we study eigenfunction statistics for the Laplacian perturbed by a delta-potential (also known as a point scatterer) on a flat torus, a popular model used to study the transition between integrability and chaos in quantum mechanics. The eigenfunctions of this operator consist of eigenfunctions of the Laplacian which vanish at the scatterer, and new, or perturbed, eigenfunctions. We show that almost all of the perturbed eigenfunctions are uniformly distributed in configuration space.     

Universal Amplitude Ratios in the Critical Two-Dimensional Ising Model on a Torus

Using results from conformal field theory, we compute several universal amplitude ratios for the two-dimensional Ising model at criticality on a symmetric torus. These include the correlation-length ratio x =lim _L (L)/L and the first four magnetization moment ratios V _2n = ²ⁿ / ^{2 n} . As a corollary we get the first four renormalized 2n-point coupling constants for the massless theory on a symmetric torus, G*_2n . We confirm these predictions by a high-precision Monte Carlo simulation.     

Solutions of Woods-Saxon Potential with Spin-Orbit and Centrifugal Terms through Nikiforov-Uvarov Method

In this study, the analytical solutions of the radial Schr¨odinger equation for the central Woods-Saxon potential together with spin-orbit interaction and centrifugal terms have been derived by using Nikiforov-Uvarov method. The energy eigenvalues and corresponding eigenfunctions of nucleons have been obtained for various values of n,l, and j quantum numbers. The obtained results using this method are in satisfactory agreement with available data in the special case.     

Fourier Series Representation of Low-Lying Eigenfunctions for a Particle on the Torus

A Fourier series method for finding the low-lying eigenfunctions and eigenvalues of the Schrödinger equation for a particle on the surface of a torus is given.