activity
20242026
collaborators

5 papers

hep-th2026

Conformal anomaly in a vector field model with auxiliary scalar field

Samuel W. P. Oliveira, Públio Rwany B. R. do Vale, Ilya L. Shapiro

The conformal anomaly has well-known ambiguities related to the possible schemes of regularization and renormalization. In case of dimensional regularization, one of the options is…

gr-qc2026

Cosmological Singularities and Quantum Particles

Samuel W. P. Oliveira, Alexander Yu. Kamenshchik

We study if there is an opportunity to describe quantum particles in the vicinity of three types of cosmological singularities, big bang-big crunch, big rip and big brake. Writing…

hep-th2025

Trace anomaly for a conformal 2D vector field model

Samuel W. P. Oliveira, Ilya L. Shapiro

The trace anomaly and anomaly-induced action are evaluated for the two-dimensional vector theory with classical conformal symmetry. Implementing local conformal symmetry while…

gr-qc2025

Bounce solutions with quantum vacuum effects of massive fields and subsequent Starobinsky inflation

Wagno Cesar e Silva, Samuel W. P. Oliveira, Ilya L. Shapiro

We extend the previous work about the cosmological solutions with a bounce without modifications of gravity or introducing an extra scalar field. The main finding was that the boun…

gr-qc2024

Pauli equation and charged spin-1/2 particle in a weak gravitational field

Samuel W. P. Oliveira, Guilherme Y. Oyadomari, Ilya L. Shapiro

Using the nonrelativistic approximation in the curved-space Dirac equation, the analog of the Pauli equation is derived for a weak gravitational field with a gauge fixing condition…