Banca de DEFESA: JUAN DAVID FONSECA JAMAICA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
DISCENTE : JUAN DAVID FONSECA JAMAICA
Data: 01/10/2026
HORA: 14:00
LOCAL: https://conferenciaweb.rnp.br/sala/juan-29
TÍTULO:

Relativistic Effects in Spin Correlations Induced by QED Scattering and Wigner Rotations

PÁGINAS: 53
RESUMO:

We study the spin correlations that, at tree level, arise in a general quantum field scattering process involving two spin-1/2 interacting particles, A and B, and a witness fermion, C, which does not participate in the scattering dynamics. First, we investigate the correlations generated by C in the process e-e+C → μ-μ+C by constructing general expressions for the reduced density matrix of the out-state, considering different initial tripartite entanglement configurations. It is found that, as indicated by the variation in the von Neumann entropy, the witness particle develops correlations when the initial state is a three-particle entangled W-state, as well as when it is initially entangled with one of the interacting particles in the Bell basis. This result is also reflected in the variation of the spin expectation values along the z- and x(y)-axes, respectively. Next, we investigate the relativistic nature of the interactions responsible for generating these correlations by extending the analysis to processes e-e- → e-e-, e-e-C → e-e-C, both studied in the center-of-mass frame and, for the former process, in a Lorentz-boosted frame, where Wigner rotations arise. Using a nonrelativistic approximation of the scattering amplitudes, we find that dipole–dipole and current–dipole interactions are responsible for the emergence of these correlations. This is further evidenced by the variation of the von Neumann entropy of one electron for the initially separable state, and of C for an initially prepared W-state. In Wigner rotations, the invariance of the entropy, and consequently of the entanglement, under local unitary transformations is preserved at the expense of the emergence of quantum coherence in the density matrix at large rapidities. As a consequence, the final states of both particles are evaluated and shown to encode information
about the scattering process through their spin expectation values. Finally, this framework is used to examine the correlations generated in one subsystem, say A or B, in the inelastic process e-e+ → μ-μ+, for which some research has reported differing results.

 

MEMBROS DA BANCA:
Presidente - Interno ao Programa - ***.800.628-** - MARCOS DONIZETI RODRIGUES SAMPAIO - UPS
Membro Titular - Examinador(a) Interno ao Programa - 3153624 - RONALDO SAVIOLI SUME VIEIRA
Membro Titular - Examinador(a) Externo ao Programa - 1156317 - ADRIANO LANA CHERCHIGLIA
Membro Titular - Examinador(a) Externo à Instituição - JOSÉ GERALDO GONÇALVES DE OLIVEIRA JÚNIOR - UESC-BA
Membro Titular - Examinador(a) Externo à Instituição - IRISMAR GONÇALVES DA PAZ - UFMG
Membro Suplente - Examinador(a) Externo à Instituição - BRIGITTE HILLER - UC