共查询到20条相似文献,搜索用时 31 毫秒
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J.E. Hirsch 《Physics letters. A》2019,383(1):83-90
We find that the bulk moment of inertia per unit volume of a metal becoming superconducting increases by the amount , with the bare electron mass and the classical electron radius. This is because superfluid electrons acquire an intrinsic moment of inertia , with the London penetration depth. As a consequence, we predict that when a rotating long cylinder becomes superconducting its angular velocity does not change, contrary to the prediction of conventional BCS-London theory that it will rotate faster. We explain the dynamics of magnetic field generation when a rotating normal metal becomes superconducting. 相似文献
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George Ruppeiner 《Physics letters. A》2019,383(8):703-706
Critical phenomena theory centers on the scaled thermodynamic potential per spin , with inverse temperature , , ordering field H, reduced temperature , critical exponents p and q, and function of . I discuss calculating with the information geometry of thermodynamics. Scaled solutions are found to obtain with three admissible functions : 1) , 2) , and 3) , where J and are constants. For , information geometry yields , consistent with the one-dimensional (1D) ferromagnetic Ising model. 相似文献
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Physically natural assumption says that any relaxation process taking place in the time interval , may be represented as a composition of processes taking place during time intervals and where is an arbitrary instant of time such that . For the Debye relaxation such a composition is realized by usual multiplication which claim is not valid any longer for more advanced models of relaxation processes. We investigate the composition law required to be satisfied by the Cole-Cole relaxation and find its explicit form given by an integro-differential relation playing the role of the time evolution equation. The latter leads to differential equations involving fractional derivatives, either of the Caputo or the Riemann-Liouville senses, which are equivalent to the special case of the fractional Fokker-Planck equation satisfied by the Mittag-Leffler function known to describe the Cole-Cole relaxation in the time domain. 相似文献
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Luke M. Butcher 《Physics letters. A》2019,383(9):843-849
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《Physics letters. A》2020,384(36):126930
We consider quantum bosons with contact interactions at the Lowest Landau Level (LLL) of a two-dimensional isotropic harmonic trap. At linear order in the coupling parameter g, we construct a large, explicit family of quantum states with energies of the form , where and are integers. Any superposition of these states evolves periodically with a period of until, at much longer time scales of order , corrections to the energies of order may become relevant. These quantum states provide a counterpart to the known time-periodic behaviors of the corresponding classical (mean field) theory. 相似文献
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《Physics letters. A》2020,384(13):126265
The exact solvability and impressive pedagogical implementation of the harmonic oscillator's creation and annihilation operators make it a problem of great physical relevance and the most fundamental one in quantum mechanics. So would be the position-dependent mass (PDM) oscillator for the PDM quantum mechanics. We, hereby, construct the PDM creation and annihilation operators for the PDM oscillator via two different approaches. First, via von Roos PDM Hamiltonian and show that the commutation relation between the PDM creation and annihilation operators, , not only offers a unique PDM-Hamiltonian but also suggests a PDM-deformation in the coordinate system. Next, we use a PDM point canonical transformation of the textbook constant mass harmonic oscillator analog and obtain yet another set of PDM creation and annihilation operators, hence an “apparently new” PDM-Hamiltonian is obtained. The “new” PDM-Hamiltonian turned out to be not only correlated with but also represents an alternative and most simplistic user-friendly PDM-Hamiltonian, ; , that has never been reported before. 相似文献
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B. Krunavakarn 《Physics letters. A》2019,383(12):1341-1344
We consider a superconducting spin valve in multiply connected superconductor-ferromagnet hybrid geometry such as a superconducting ring enclosed a ferromagnetic metal, in the framework of linearized Usadel equations. We simplify our model by considering the presence of the exchange field in the superconducting ring which allows us to manipulate magnetization orientations in parallel or antiparallel configurations by switching the weaker exchange field. In such geometry the superconducting ground state is activated to higher orbital states characterized by the nonvanishing vorticity parameters L which will be the energetically favorable superconducting state in some ranges of the proximity superconductor-ferromagnet region. The competing effects caused by the exchange interactions and the orbital effect, are analyzed through the nonmonotonic dependence of the superconducting critical temperature on the radius of the ferromagnetic core. The analytic formula is obtained within the single mode approach and the analysis of the spin switch effect is given. 相似文献
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《Physics letters. A》2019,383(25):3037-3042
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We have investigated the spin and orbital moments of Ir-based double perovskites with (n = 3, 4, 5) states by local spin-density approximation with spin-orbital coupling and Hubbard correlation (LSDA+SOC+U). Our calculations reveal that the ratio of orbital to spin momentum approaches to certain values for the double perovskites with different 5dn (n = 3, 4, 5) shell fillings. Based on d orbits, a spin-orbital coupling model with exchange splitting is proposed and it can well describe the ratio of angular momentums for the compounds. Our model calculations reveal that is determined by the exchange splitting, spin-orbital coupling as well as the state of shell filling. Our model is well corroborated by the experiments and density-functional calculations. 相似文献
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In this paper, we discuss a method based on wavelet analysis for the study of the q-index of the Gaussian distribution. We derive q-index from the scale index, , using the expression; where is a wavelet based tool for measuring the degree of aperiodicity of a dynamical system in the range of . We show that this expression gives consistent results with the numerical approach of q-Gaussian distribution which determines the degree of non-extensivity of a dynamical system in the range of . We also suggest a new entropy calculation method based on the normalized inner scalogram for studying the chaotic characteristics of nonlinear dynamical systems. 相似文献
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We propose two new type sine hyperbolic potentials and . They may become single- or double-well potentials depending on the potential parameters and k. We find that its exact solutions can be written as the confluent Heun functions , in which the energy level E is involved inside the parameter η. The properties of the wave functions, which is strongly relevant for the potential parameters and k, are illustrated. 相似文献