Título:	Symplectic density matrix
Autor(es):	Amorim, Ronni Geraldo Gomes de Santana, Ademir Eugênio de
ORCID:	https://orcid.org/0000-0003-0065-797X
Afiliação do autor:	Universidade de Brasília, Faculdade Gama Universidade de Brasília, International Center of Physics
Assunto:	Matriz de densidade simplética
Data de publicação:	30-Mai-2023
Editora:	Springer
Referência:	AMORIM, Ronni G. G.; SANTANA, Ademir E. Symplectic density matrix. Brazilian Journal of Physics, [S. l.], v. 53, art. n. 102, 2023. DOI: https://doi.org/10.1007/s13538-023-01272-2.
Abstract:	The quasi amplitude of probability, a concept associated with the Wigner function, is used to introduce the notion of sym plectic density matrix, ?. The Liouville-Von Neumann equation is derived in phase space by using symmetry. The physi cal content of ? is analyzed in detail, in particular with the study of the classical limit. The first application addresses the problem of quark-antiquark interaction, described by the so-called Cornell potential. The matrix ? is calculated, providing a phase space description of the quark-antiquark state. For the model considered here, the quark confinement is derived, such that the distance of confinement is about 4 GeV−1 . This result improves theoretical calculations in the literature, approach ing to the order of experimental results. Another application is the calculation of ? considering mixed state systems. Since ? is a density of probability, the entropy is defined without ambiguity, and as such the Gibbs ensemble is introduced for a quantum system in the phase space representation. Then a harmonic oscillator system at finite temperature is studied. The second mixed state system is a maximally entangled bipartite state. In these applications, when it is possible, the nature of ? is compared with the Wigner function.
Unidade Acadêmica:	Faculdade UnB Gama (FGA) Instituto de Física (IF)
DOI:	https://doi.org/10.1007/s13538-023-01272-2
Versão da editora:	https://link.springer.com/article/10.1007/s13538-023-01272-2
Aparece nas coleções:	Artigos publicados em periódicos e afins

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