scholarly journals Unified Transform method for the Schr¨odinger Equation on a Simple Metric Graph

Author(s):  
Gulmirza Khudayberganov ◽  
Zarifboy A. Sobirov ◽  
Mardonbek R. Eshimbetov

Integral-representation of solutions of the initial-boundary value problems for the Schr¨odinger equation on simple metric graphs was obtained with the use of the Fokas method. This method uses special gen- eralization of the Fourier transform that is referred to as the unified transform. Obtained representation of solutions of the problem for open and closed simple star graphs allows one to identify transmitted, reflected and trapped waves at the graph branching point

2011 ◽  
Vol 152 (3) ◽  
pp. 473-496 ◽  
Author(s):  
DAVID A. SMITH

AbstractWe study initial-boundary value problems for linear evolution equations of arbitrary spatial order, subject to arbitrary linear boundary conditions and posed on a rectangular 1-space, 1-time domain. We give a new characterisation of the boundary conditions that specify well-posed problems using Fokas' transform method. We also give a sufficient condition guaranteeing that the solution can be represented using a series.The relevant condition, the analyticity at infinity of certain meromorphic functions within particular sectors, is significantly more concrete and easier to test than the previous criterion, based on the existence of admissible functions.


2019 ◽  
Vol 8 (1) ◽  
pp. 15-20
Author(s):  
Khaled A. Ishag ◽  
Faris Azhari Okasha

In this paper, we apply analytical method (homotopy perturbation transformmethod), for solving extensible beam, we discuss certain initial- boundary value problems for the nonlinear equation. This equation wasproposed by Woiniwsky- Krieger as a model for transverse deflection of an extensible beam of natural length whose ends are held a fixed distance apart.


Author(s):  
A. Batal ◽  
A. S. Fokas ◽  
T. Özsarı

We obtain solution representation formulae for some linear initial boundary value problems posed on the half space that involve mixed spatial derivative terms via the unified transform method (UTM), also known as the Fokas method. We first implement the method on the second-order parabolic PDEs; in this case one can alternatively eliminate the mixed derivatives by a linear change of variables. Then, we employ the method to biharmonic problems, where it is not possible to eliminate the cross term via a linear change of variables. A basic ingredient of the UTM is the use of certain invariant maps. It is shown here that these maps are well defined provided that certain analyticity issues are appropriately addressed.


2019 ◽  
Vol 22 (3) ◽  
pp. 795-806
Author(s):  
Jorge Sanchez-Ortiz ◽  
Francisco J. Ariza-Hernandez ◽  
Martin P. Arciga-Alejandre ◽  
Eduard A. Garcia-Murcia

Abstract In this work, we consider an initial boundary-value problem for a stochastic evolution equation with fractional Laplacian and white noise on the first quadrant. To construct the integral representation of solutions we adapt the main ideas of the Fokas method and by using Picard scheme we prove its existence and uniqueness. Moreover, Monte Carlo methods are implemented to find numerical solutions for particular examples.


1998 ◽  
Vol 5 (1) ◽  
pp. 25-48
Author(s):  
T. Burchuladze ◽  
D. Burchuladze

Abstract Lord–Shulman's system of partial differential equations of generalized thermoelasticity [Green and Lindsay, J. Elasticity 2: 1–7, 1972] is considered, in which the finite velocity of heat propagation is taken into account by introducing a relaxation time constant. General aspects of the theory of boundary value and initial-boundary value problems and representation of solutions by series and quadratures are considered using the method of a potential.


2019 ◽  
Vol 150 (5) ◽  
pp. 2387-2416
Author(s):  
Baoqiang Xia

AbstractThe unified transform method (UTM) or Fokas method for analyzing initial-boundary value (IBV) problems provides an important generalization of the inverse scattering transform (IST) method for analyzing initial value problems. In comparison with the IST, a major difficulty of the implementation of the UTM, in general, is the involvement of unknown boundary values. In this paper we analyze the IBV problem for the massive Thirring model in the quarter plane, assuming that the initial and boundary data belong to the Schwartz class. We show that for this integrable model, the UTM is as effective as the IST method: Riemann-Hilbert problems we formulated for such a problem have explicit (x, t)-dependence and depend only on the given initial and boundary values; they do not involve additional unknown boundary values.


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