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Cesar Augusto Zen Vasconcellos

Publications and source records attributed to Cesar Augusto Zen Vasconcellos.

2 recordsLinked to original sources

Curvture Regularization and Dynamical Vacuum Structure in Pseudo-Complex General Relativity

Whether classical spacetime remains welldefined at arbitrarily high curvature is a central question. In general relativity, singularities signal the breakdown of the classical description, motivating modifications of spacetime's short-distance structure. Pseudocomplex general relativity (pcGR) extends spacetime geometry to pseudo-complex coordinates, naturally introducing two metric sectors, the physical metric gμν and an auxiliary field fμν. The magnitude of the pseudo imaginary component defines the invariant acceleration scale a0, a direct consequence of the pseudo-complex structure. The simultaneity condition, requiring both idempotent sectors to satisfy the pseudo-complex Einstein equations independently, fixes the auxiliary field algebraically, with no new propagating degrees of freedom, and sets a lower bound on the lapse that regularizes curvature. The regularization is achieved through the combined effect of the lapse-gap condition eν(r) gt. a0, which ensures the radial metric component remains nondegenerate, together with the regularity conditions at the areal-radius origin, B(0) = 1 and B'(0) = 0, which emerge naturally from the pseudo-complex geometry. These conditions jointly eliminate the Schwarzschildtype curvature divergence, rather than the gap condition acting alone.

gr-qc

A comparative study of Compact Objects using 3 models: Walecka Model, PAL Model, and M.I.T. Bag Model

Compact objects are the name used to classify the following objects: white dwarf, neutron star and black holes. In addition to them, some authors have suggested that in the core of a neutron star we may have the quarks u,d,s and c. In this work we investigate the structure of neutron star and strange star, described by the Tolman-Openheimer-Volkof equations. For the neutron star, we used the relativistic EoS from Walecka's model and the non-relativistic EoS PAL model. For the strange star, we used the M.I.T. bag model. We obtain results for the mass-radius relation and then we compared ours results with the actual pulsar data recently observed PSR J1614-2230 with a mass $1.97\pm 0.04\ M_{\odot}$.

nucl-th