My name is Alejandro Farid Cantun Estrella – I am a mexican physicist researching the foundations and phenomenology of semiclassical gravity, modern cosmology and higher-dimensional gravity.

Research interests

  • Bridging quantum field theory with general relativity, exploring topics such as quantum back‑reaction, and the interface between early‑universe inflationary models and quantum fluctuations.

  • Studying probes of higher-dimensional gravity, such as lensing, as well as possible connections to string-inspired models, e.g. topological defects, conical spacetimes.

Specific research problems

Dimensional regularization of QFT in curved backgrounds: Exact global methods of renormalization based on meromorphic continuation of divergent integrals.

This line of reseach continues the program started by DeWitt, Schwinger, Bunch, Davies and so on, on the finite and convariant definition of renormalized correlators in semiclassical gravity. This paradigm opposes the modern effective techniques of UV and IR cut-off’s and renormalization by radiative corrections.

Objective: Build a precise mathematical foundation to justify the approximative, perturbative and semi-empirical approach of Effective Field Theory commonly used in particle physics.

Higher-dimensional exact solutions to the Einstein field equations: lensing of exotic compact objects and alternative void models of static expansion which could account for the cosmological constant.

Objectives:

  • Find exotic exact solutions to General Relavity in order to study effective models of lensing.
  • Understand how Einstein gravity behaves in models with highly anistotropic stress.
  • Find string-inspired models which can be connected to effective objects comming from string theory.
  • Understand how the stability and cosmic censorship of exotic solutions can be recovered using semiclassical quantum corrections.