http://dspace.nbuv.gov.ua:80/handle/123456789/114792 Sun, 05 Apr 2026 08:59:51 GMT 2026-04-05T08:59:51Z http://dspace.nbuv.gov.ua:80/bitstream/id/341589/ http://dspace.nbuv.gov.ua:80/handle/123456789/114792 http://dspace.nbuv.gov.ua:80/handle/123456789/121330 Critical sound attenuation of three-dimensional Ising systems Prudnikov, P.V.; Prudnikov, V.V. The field-theoretic description of dynamic critical effects of the disorder on acoustic anomalies near the temperature of second-order phase transition is considered for three-dimensional Ising-like systems. The calculations of sound attenuation in high temperature phase for pure and diluted Ising-like systems near the critical point are presented. The dynamic scaling function for critical attenuation coefficient is calculated. The effect of the quenched disorder on asymptotic behaviour of the critical ultrasonic anomalies is discussed. Sun, 01 Jan 2006 00:00:00 GMT http://dspace.nbuv.gov.ua:80/handle/123456789/121330 2006-01-01T00:00:00Z http://dspace.nbuv.gov.ua:80/handle/123456789/121329 A class of solvable models in Condensed Matter Physics Mancini, F. In this paper, we show that there is a large class of fermionic systems for which it is possible to find, for any dimension, a finite closed set of eigenoperators and eigenvalues of the Hamiltonian. Then, the hierarchy of the equations of motion closes and analytical expressions for the Green’s functions are obtained in terms of a finite number of parameters, to be self-consistently determined. Several examples are given. In particular, for these examples it is shown that in the one-dimensional case it is possible to derive by means of algebraic constraints a set of equations which allow us to determine the self-consistent parameters and to obtain a complete exact solution. Sun, 01 Jan 2006 00:00:00 GMT http://dspace.nbuv.gov.ua:80/handle/123456789/121329 2006-01-01T00:00:00Z http://dspace.nbuv.gov.ua:80/handle/123456789/121328 Absorption coefficient of nearly transparent liquids measured using thermal lens spectrometry Cabrera, H.; Marcano, A.; Castellanos, Y. We use an optimized pump-probe mode-mismatched thermal lens scheme to determine the optical absorption coefficient and thermal diffusivity of ethanol, benzene, acetone, methanol, toluene and chloroform. In this scheme the excitation beam is focused in the presence of a collimated probe beam. The agreement between experimentally obtained results and values reported in the literature is good. Sun, 01 Jan 2006 00:00:00 GMT http://dspace.nbuv.gov.ua:80/handle/123456789/121328 2006-01-01T00:00:00Z http://dspace.nbuv.gov.ua:80/handle/123456789/121327 Entanglement production under electron phonon interaction in a quantum dot Lopez, A.; Medina, E. We consider the quantum dot entangler device introduced by Oliver et al. [1] coupled to a single phonon mode. While we take the phonon interaction to all orders, we perform a fourth order calculation in electron-dot coupling. Using the Von Neumann entropy we measure the degree of entanglement. We find that the phonon mechanism habilitates single electron processes which manifest themselves as decoherent processes. Sun, 01 Jan 2006 00:00:00 GMT http://dspace.nbuv.gov.ua:80/handle/123456789/121327 2006-01-01T00:00:00Z