scholarly journals Renormalized spectrum of quasiparticle in limited number of states, strongly interacting with two-mode polarization phonons at T=0 K

2021 ◽  
Vol 24 (1) ◽  
pp. 13705
Author(s):  
M.V. Tkach ◽  
Ju.O. Seti ◽  
O.M. Voitsekhivska

Within unitary transformed Hamiltonian of Fröhlich type, using the Green's functions method, exact renormalized energy spectrum of quasiparticle strongly interacting with two-mode polarization phonons is obtained at T=0 K in a model of the system with limited number of its initial states. Exact analytical expressions for the average number of phonons in ground state and in all satellite states of the system are presented. Their dependences on a magnitude of interaction between quasiparticle and both phonon modes are analyzed.

2011 ◽  
Vol 13 ◽  
pp. 01002
Author(s):  
R. Alkofer ◽  
M. Mitter ◽  
B.J. Schaefer

2004 ◽  
Vol 71 (2) ◽  
pp. 273-282 ◽  
Author(s):  
Wan-Lee Yin

Degenerate and extra-degenerate anisotropic elastic materials have repeated material eigenvalues whose multiplicity is greater than the number of independent eigensolutions. Using basic elasticity relations, a simple, direct proof is given to show that higher-order eigensolutions may be obtained from the analytical expressions of the zeroth-order eigensolutions according to the derivative rule. These higher-order eigensolutions contribute to the complexity of the general solutions of degenerate and extra-degenerate materials, and to the analytical difficulties inherent in such cases including isotropic elasticity. For all types of anisotropic materials, the general solution is given specific forms to obtain Green’s functions of several domains with straight or elliptical boundaries. These results, presented in fully explicit expressions, extend Green’s functions of nondegenerate materials to degenerate and extra-degenerate cases that have not been explored previously.


2009 ◽  
Vol 3 (2) ◽  
pp. 282-302 ◽  
Author(s):  
E. Bendito ◽  
A.M. Encinas ◽  
A. Carmona

In this work we analyze the boundary value problems on a path associated with Schr?dinger operators with constant ground state. These problems include the cases in which the boundary has two, one or none vertices. In addition, we study the periodic boundary value problem that corresponds to the Poisson equation in a cycle. Moreover, we obtain the Green's function for each regular problem and the eigenvalues and their corresponding eigenfunctions otherwise. In each case, the Green's functions, the eigenvalues and the eigenfunctions are given in terms of first, second and third kind Chebyshev polynomials.


Author(s):  
Francisco J. Valdés-Parada

Abstract This work is devoted to briefly describe the scientific achievements of J. Alberto Ochoa-Tapia and his research group along almost three decades. The motivation for performing this review is not only to acknowledge his contributions, but also to share with the scientific community a brilliant scientific career. Although an exhaustive and complete review is beyond the scope of this paper, many of Alberto’s scientific contributions are briefly described. In addition, special attention is dedicated to three subjects, namely: Chang’s unit cell, the derivation of boundary conditions between a porous medium and a fluid and the use of Green’s functions to solve boundary-value problems. The first one is a convenient approach to derive analytical expressions of effective-medium coefficients resulting from the volume averaging method. The second one is Alberto’s most referenced work and it is of paramount importance since it provides the means to complete the statement of multiscale modeling. The third focus of attention is about the use of Green’s functions to solve nonlinear boundary-value problems in an efficient manner. Finally, his current and future works are discussed.


2015 ◽  
Vol 29 (17) ◽  
pp. 1550081
Author(s):  
Alexander V. Zhukov ◽  
Roland Bouffanais ◽  
Anastasiya V. Pak ◽  
Mikhail B. Belonenko

The indirect spin–spin interaction between impurities in a non-Fermi quantum liquid system is theoretically investigated in this paper. The poles of the Green’s functions are shown to be responsible for the observed excitation spectra. Specifically, the anti-de Sitter/conformal field theory (AdS/CFT) correspondence is used to gain access to the analytical expressions of the Green’s functions for our particular problem.


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