Controle magnetoelástico das correlações quânticas e sensibilidade ao campo magnético em um dímero de Heisenberg de spin 1/2

• Ano de defesa: 2026
• Autor(a) principal: Souza, Eduardo Wallace Braga de
• Outros Autores: https://orcid.org/0009-0003-8311-2525
• Orientador(a): Santos, Onofre Rojas
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Lavras; Instituto de Ciências Naturais (ICN)
• Programa de Pós-Graduação: Programa de Pós-Graduação em Física
• País: brasil
• Palavras-chave em Português: Dímero de Heisenberg; Magnetoelasticidade; Correlações quânticas; Informação de Fisher Quântica; Correções magnetoelásticas de segunda ordem; Heisenberg dimer; Magnetoelasticity; Second-order corrections; Quantum correlations; Quantum Fisher information
• Área do conhecimento CNPq: Física da Matéria Condensada
• Link de acesso: https://repositorio.ufla.br/handle/1/61143

This work investigates magnetoelastic effects in a spin-1/2 Heisenberg dimer by explicitly considering the influence of internal vibrational modes on its thermal, magnetic, and quantum properties. Unlike the usual linear approach, the developed model incorporates second-order magnetoelastic corrections in the relative displacement between spins, providing a more realistic description of the coupling between magnetic and vibrational degrees of freedom. Through the diagonalization of the magnetoelastic Hamiltonian and the construction of the partition function, renormalized energies, effective vibrational frequencies, and thermal populations associated with different spin sectors are obtained. Based on these quantities, the mean magnetoelastic displacement, vibrational fluctuations, magnetization, magnetic susceptibility, and ground-state phase boundaries are analyzed. In addition, the work investigates thermal quantum correlations through concurrence, local quantum uncertainty, and quantum Fisher information, emphasizing the effects produced by thermal population redistribution and vibrational renormalization of the energy spectrum. The results show that second-order corrections significantly modify the stability of magnetic phases, the energy gaps between eigenstates, and the robustness of quantum correlations, highlighting the relevance of magnetoelastic effects in low-dimensional quantum systems.