scholarly journals On Exact Series Solution of Strongly Coupled Mixed Parabolic Problems

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Vicente Soler ◽  
Emilio Defez ◽  
M. V. Ferrer ◽  
J. Camacho

This paper studies the construction of the exact solution for parabolic coupled systems of the type , , , , , and , where , , , and are arbitrary matrices for which the block matrix is nonsingular, and is a positive stable matrix.

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Vicente Soler ◽  
Emilio Defez ◽  
José Antonio Verdoy

This paper continues with the construction of the exact solution for parabolic coupled systems of the typeut=Auxx,A1u(0,t)+B1ux(0,t)=0,A2u(l,t)+B2ux(l,t)=0,0<x<1,t>0, andu(x,0)=f(x), whereA1,A2,B1, andB2are arbitrary matrices for which the block matrix(A1B1A2B2)is nonsingular, andAis a positive stable matrix. Although this problem has been solved in the literature (Soler et al., 2013), in this work we are using completely new conditions.


2014 ◽  
Vol 2014 ◽  
pp. 1-10
Author(s):  
Vicente Soler ◽  
Emilio Defez ◽  
Roberto Capilla ◽  
José Antonio Verdoy

An exact series solution for nonhomogeneous parabolic coupled systems of the typeut-Auxx=Gx, t, A1u0, t+B1ux0, t=0, A2ul, t+B2uxl, t=0, 0<x<1, t>0, ux, 0=fx, whereA1, A2, B1, andB2are arbitrary matrices for which the block matrix is nonsingular, andAis a positive stable matrix, is constructed.


Filomat ◽  
2019 ◽  
Vol 33 (3) ◽  
pp. 897-915
Author(s):  
Emilio Defez ◽  
Vicente Soler ◽  
Sergio Romero-Vivó ◽  
José Verdoy

In this paper an exact series solution for homogeneous parabolic coupled systems is constructed using a projection method. An illustrative example is given.


2000 ◽  
Vol 43 (2) ◽  
pp. 269-293 ◽  
Author(s):  
L. Jódar ◽  
E. Navarro ◽  
J. A. Martin

AbstractThis paper deals with the construction of exact and analytical-numerical solutions with a priori error bounds for systems of the type ut = Auxx, A1u(0, t) + B1ux (0, t) = 0, A2u (1, t) + B2ux (1, t) = 0, 0 < x < 1, t > 0, u(x, 0) = f(x), where A1, A2, B1 and B2 are matrices for which no simultaneous diagonalizable hypothesis is assumed, and A is a positive stable matrix. Given an admissible error ε and a bounded subdomain D, an approximate solution whose error with respect to an exact series solution is less than ε uniformly in D is constructed.


2020 ◽  
Vol 75 (8) ◽  
pp. 803-807
Author(s):  
Svend-Age Biehs ◽  
Achim Kittel ◽  
Philippe Ben-Abdallah

AbstractWe theoretically analyze heat exchange between two quantum systems in interaction with external thermostats. We show that in the strong coupling limit the widely used concept of mode temperatures loses its thermodynamic foundation and therefore cannot be employed to make a valid statement on cooling and heating in such systems; instead, the incorrectly applied concept may result in a severe misinterpretation of the underlying physics. We illustrate these general conclusions by discussing recent experimental results reported on the nanoscale heat transfer through quantum fluctuations between two nanomechanical membranes separated by a vacuum gap.


1999 ◽  
Vol 77 (11) ◽  
pp. 1810-1812 ◽  
Author(s):  
Alex D Bain

Strongly coupled spin systems provide many curious and interesting effects in NMR spectra, one of which is the presence of unexpected (from a first-order viewpoint) lines. A physical reason is given for the presence of these combination lines. The X part of the spectrum of an ABX spin system is analysed as an example. For an ABX system, it is well known that the AB nuclei give a spectrum consisting of two AB-type spectra, corresponding to the two orientations of the X nucleus. It can also be shown that the X part of the spectrum corresponds to the X nucleus undergoing a transition in the presence of an AB-like spin system. For weakly coupled systems, the four observed lines correspond to the four different orientations of the A and B nuclei. For a strongly coupled system, two additional lines may appear, the combination lines. The resulting six lines correspond to the four spin orientations, plus the two zero-quantum transitions. It is shown that these six lines are such that there is no net excitation of the AB-like spin system associated with the X transitions. There is no AB coherence created directly by a pulse applied to X. AB coherence is created as the system evolves, and this is responsible for many of the curious effects. This is shown to be true for all spin sub-systems, which are weakly coupled to a strongly coupled sub-system.Key words: NMR, strong coupling, second-order spectra, ABX spin system, combination lines, spectral analysis.


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