Quantum field theory, relativistic fluid solutions, black hole physics, and mathematical methods in physics.

Jorge L. deLyra (born May 20, 1954, São Paulo, Brazil) is a Brazilian theoretical physicist and Associate Professor at the Institute of Physics of the University of São Paulo (USP), where he has served since 1989 and is now retiring after more than 35 years of academic activity. He earned his bachelor’s (1976) and master’s (1979) degrees in physics from USP, working under Prof. Henrique Fleming, and later completed his PhD in physics at Yale University in 1987 under the supervision of Prof. Lee Smolin. He subsequently held a postdoctoral position at the University of Texas at Austin with Prof. Bryce S. DeWitt (1987–1989). In 1993, he defended his “Livre-Docência” thesis on Quantum Field Theory and Space-Time Geometry. Professor deLyra’s research focuses on general relativity, relativistic fluid solutions, black-hole limits of polytropes, dark matter halo models, and connections between general relativity and quantum field theory. He has published extensively in journals such as General Relativity and Gravitation and the International Journal of Modern Physics A. In addition to his research in physics, he has contributed to mathematical analysis, particularly Fourier theory and complex analysis of real functions, with several works available on arXiv and in peer-reviewed journals. He is also the author of books on mathematical methods for physics and engineering, including volumes on complex calculus and Fourier transforms. Reference: Shell Solutions in General Relativity: Repulsive Singularities, Quantum Remnants, and Implications for Dark Matter  The Einstein field equations with matter within shells, in the static and spherically symmetric case, was discovered. In this talk these new solutions are described in the case of the polytropic equation of state, and their main consequences for the structure of the theory are discussed. Due to the development of these solutions new aspects of the concept of spacetime singularities in general relativity were uncovered, namely that there are repulsive singularities. The existence of these new solutions also led to radically different conclusions about the concept of gravitational collapse, as well as about the internal geometry and structure of black holes. The analysis of sequences of shell solutions that approach the exterior Schwarzschild geometry led to an unexpected connection with the quantumaspects of physics. We were able to reproduce, by purely classical means,the two main conclusions of the study of quantum mechanics in the exterior Schwarzschild solution, leading to the conclusion that general relativity contains remnants of an underlying quantum structure. Further ongoing work explores the connection of general relativity with lattice quantum field theory, which ultimately leads to the integration of general relativity with quantum field theory, a problem known by the misnomer of "quantum gravity". This connection is made through the standard model of particle physics and the spontaneous symmetry breaking involving the Higgs field. The same set of ideas involved in the new shell solutions, as well as this relationship between general relativity and quantum field theory, also lead to the proposition of a fairly simple solution to the problem of the "dark matter" halos in galaxies. This identifies the "dark matter", another misnomer, with the vacuum expectation value of the Higgs field, and correctly predicts the flat velocity curves of galaxies.