My name is Alejandro Farid Cantun Estrella, and I am a physicist trained at the National Autonomous University of Mexico (UNAM). This project originated as my undergraduate thesis in theoretical physics. The original manuscript was written in Spanish and is currently being translated, revised, and substantially expanded into English as part of its development into a graduate-level book. The original thesis is publicly available in the UNAM institutional repository.
The work was formally submitted for consideration for an academic medal. Although it did not receive the award, the competition at the Institute of Physics at UNAM was particularly strong that year, with many submissions coming from the experimental side of physics, often supported by conference proceedings or journal publications.
As is sometimes the case in physics, theoretical work—especially when it is foundational rather than immediately phenomenological—can be less visible in such contexts. Nevertheless, the thesis established a solid conceptual and mathematical foundation, and it was precisely this work that convinced me the material deserved further development beyond the undergraduate level.
Since completing the thesis, I have continued working as an independent researcher while applying to graduate programs. During this time, I have become deeply familiar with the practices of theoretical research and have submitted two research articles on advanced topics in mathematical and gravitational physics, including dimensional regularization of quantum field theory in curved spacetime and effective geometries interpreted as topological defects in gravity.
This progression—from undergraduate thesis, to independent research, to the development of a coherent manuscript—naturally led to the present project: the expansion of these notes into a rigorous, graduate-level book on inflationary cosmology and cosmological perturbations. The goal is not only to present technical results, but to provide a clear, self-contained exposition that reflects how the subject is actually learned and understood through research.
In this sense, the book represents both a continuation of my early academic work and a reflection of my current stage as a developing theoretical physicist. My research manuscripts and ongoing work can be found on my personal webpage.