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81.
Using the third-order WKB approximation, we evaluate the quasinormal frequencies of massless Dirac field perturbation around a Reissner Nordstrom black hole surrounded by a static and spherically symmetric quintessence. We study the variation of quasinormal frequencies with the quintessential state parameter ε, the total angular momentum number |k|, the charge Q, and the overtone number n changes, respectively. Moreover, from the results we obtained, we find that the massless Dirac field damps more slowly due to the presence of quintessence. 相似文献
82.
83.
The linearized vorticity equation serves to model a number of wave phenomena in geophysical fluid dynamics. One technique that has been applied to this equation is the geometrical optics, or multi-dimensional WKB technique. Near caustics, this technique does not apply. A related technique that does apply near caustics is the Lagrange Manifold Formalism. Here we apply the Lagrange Manifold Formalism to determine an asymptotic solution of the linearized vorticity equation and to study associated wave phenomena on the caustic curve. 相似文献
84.
85.
The authors study the compressible limit of the nonlinear Schr(o)dinger equation with different-degree small parameter nonlinearities in small time for initial data with Sobolev regularity before the formation of singularities in the limit system. On the one hand, the existence and uniqueness of the classical solution are proved for the dispersive perturbation of the quasi-linear symmetric system corresponding to the initial value problem of the above nonlinear Schr(o)dinger equation. On the other hand, in the limit system,it is shown that the density converges to the solution of the compressible Euler equation and the validity of the WKB expansion is justified. 相似文献
87.
We consider the following Cauchy problem for weakly coupled systems of semilinear damped elastic waves with a power source nonlinearity in three dimensions: where with b2 > a2 > 0 and θ ∈ [0,1]. Our interests are some qualitative properties of solutions to the corresponding linear model with vanishing right‐hand side and the influence of the value of θ on the exponents p1,p2,p3 in to get results for the global (in time) existence of small data solutions. 相似文献
88.
T. M. Dunster 《Studies in Applied Mathematics》2020,145(3):500-536
Asymptotic solutions are derived for inhomogeneous differential equations having a large real or complex parameter and a simple turning point. They involve Scorer functions and three slowly varying analytic coefficient functions. The asymptotic approximations are uniformly valid for unbounded complex values of the argument, and are applied to inhomogeneous Airy equations having polynomial and exponential forcing terms. Error bounds are available for all approximations, including new simple ones for the well-known asymptotic expansions of Scorer functions of large complex argument. 相似文献
89.
The modulational theory of nonlinear gravity-wave in fluid with varying depth and nonuniform current
By means of WKB expansions, new fourth order evolution equations are derived for two-dimensional Stokes waves over the bottom
with arbitrary depth. The effects of slowly varying depthh=h(ε
2x) and currentU=U(ε
2x,ε2t,ε4z) on the evolution of a packet of Stokes waves are considered as well. In addition, numerical simulation is performed for
the evolution of single envelope by finite-difference method.
Project supported by National Natural Science Foundation of China and Centre of Advanced Academic Research of Zhongshan University. 相似文献
90.
Let H(?)=?? 2d2/dx 2+V(x) be a Schrödinger operator on the real line, W(x) be a bounded observable depending only on the coordinate and k be a fixed integer. Suppose that an energy level E intersects the potential V(x) in exactly two turning points and lies below V ∞=lim?inf?|x|→∞ V(x). We consider the semiclassical limit n→∞, ?=? n →0 and E n =E where E n is the nth eigenenergy of H(?). An asymptotic formula for 〈n|W(x)|n+k〉, the non-diagonal matrix elements of W(x) in the eigenbasis of H(?), has been known in the theoretical physics for a long time. Here it is proved in a mathematically rigorous manner. 相似文献