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Last name: PÉREZ FERNÁNDEZ
First name: Pedro
El trabajo se estructura en 6 capítulos. El capítulo 1 posee fundamentalmente un carácter de introducción teórica a las herramientas de campo medio que se usan en los diferentes modelos que se presentan, además de introducirse otros conceptos que aparec e
We study the thermodynamics of the full version of the Dicke model, including all the possible values of the total angular momentum j, with both microcanonical and canonical ensembles. We focus on both the excited-state quantum phase transition, appearing in the microcanonical description of the maximum angular momentum sector, j=N/2, and the...
At present, the research on invariant functions for algebras is very extended since Hrivnák and Novotný defined in 2007 the invariant functions y and j as a tool to study the Inönü–Wigner contractions (IW-contractions), previously introduced by those authors in 1953. In this paper, we introduce a new invariant two-parameter function of...
Analytical results beyond the mean-field-limit approximation for several observables of the two-dimensional limit of the vibron model are presented. Finite-size scaling exponent values are also analytically derived. The computed corrections and scaling exponents are compared to numerical calculations for this algebraic model, based on a bosonic...
The basic Lipkin-Meshkov-Glick model displays a second-order ground-state quantum phase transition and an excited-state quantum phase transition (ESQPT). The inclusion of an anharmonic term in the Hamiltonian implies a second ESQPT of a different nature. We characterize this ESQPT using the mean field limit of the model. The alternative ESQPT,...
The standard Lipkin-Meshkov-Glick (LMG) model undergoes a second-order ground-state quantum phase transition (QPT) and an excited-state quantum phase transition (ESQPT). The inclusion of an anharmonic term in the LMG Hamiltonian gives rise to a second ESQPT that alters the static properties of the model [Gamito, Phys. Rev. E 106, 044125...