About Me

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Hello, and welcome to my professional log. My name is Luis A. Quiroz, and I am a data science-driven physicist and current Master's student in Astrophysics at UNAM's Astronomy and Physics Institutes. I specialize in theoretical cosmology, numerical simulations, data visualization, and the application of computational methods to complex mathematical physics problems.

Currently, I am developing my Master’s Thesis Project (MTP), tentatively titled Effective Equation of State and Gravitational Particle Production in Inflationary Models, under the direction of Dr. Marcos A. García García. In this research, I write modular Python code to run numerical simulations that analyze the dynamics of inflaton and spectator fields during the reheating transition. For non-physics people, that means studying the early Universe energy fields that would become fundamental particles and could explain modern astrophysical questions like dark matter (DM) or the still-happening expansion of the space itself.

Beyond theoretical cosmology, my academic and professional trajectory heavily integrates data science (DS), machine learning (ML), and artificial intelligence (AI). My background includes specialized coursework in neural networks (NN) and AI modeling - I took Dr. Jose Antonio Vazquez Mata's course on NN as a bachelor at UNAM's Faculty of Science, I am currently revisiting Dr. Mehryar Mohri's course on Foundations of ML at New York University (NYU) and taking the Introduction to Modern AI lectures given by Dr. Zico Kolter at Carnegie Mellon University (CMU) - allowing me to apply advanced computational architectures to rigorous data sets.

I have actively applied these analytical and programming skills in industry environments. Recently, I have worked as an AI Trainer, contributing to human-in-the-loop learning pipelines and providing high-quality annotations for natural language processing (NLP) tasks. This includes direct experience with Reinforcement Learning Through Human Feedback (RLHF), refining large language model (LLM) behavior in real-time evaluations.

Effective scientific communication and interdisciplinary research are also central to my methodology. Over the years, I have cultivated a strong foundation in academic and analytical writing, authoring award-winning essays (Concursos Interpreparatorianos 2017-2019) spanning both physics and the humanities, such as Natural and Artificial Satellites and Why Study Philosophy Today?. I love a good research project!

Finally, as a polyglot with proficiency in English, German, Italian, and Portuguese, I am equipped to collaborate effectively across international and multidisciplinary teams. Whether I am modeling financial workflows, training language models, or simulating the early universe, my goal is always to leverage computational tools to extract meaningful insights from complex systems.

If for some reason you do not already have a copy of my Résumé (or CV) here you can find one.

• Click Here for CV! (PDF)

Hope you have a wonderful day/night/whatever! And as John Lennon said at the end of The Beatles rooftop concert, I hope we passed the audition!

Master's Thesis Project

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Effective Equation of State and Gravitational Particle Production in Inflationary Models

Advisor: Dr. Marcos A. García García

Institution: Institute of Physics, UNAM

The primary objective of the project is to rigorously characterise the relic abundance of a dark matter candidate produced exclusively through gravitational interaction during the transition between cosmic inflation and the inflationary reheating phase. In particular, we study the dynamical behaviour of a spectator scalar field decoupled from the inflaton sector, analysing how the coherent oscillations of the inflationary background modulate the spacetime metric and induce non-thermal particle production phenomena.

Work Completed and Achievements

During the previous semesters, the research plan has focused on:

1. Exploration of T-Model Type Potentials: In the first stage of the project, the inflation dynamics using T-model type potentials were evaluated in detail, employing recent literature in the sector as a formal reference framework (particularly the analytical formalism presented in arXiv:2502.20471). The slow-roll conditions and the end of inflation were derived for these potentials. In terms of programming, the work focused on the dynamics of the inflationary field:
   • The evolution of the inflaton during inflation and its transition towards the oscillation phase (reheating) was studied for a T-model and various values of k, verifying that the densities obtained agreed with the theoretical forms (~ a^-6k/(k+2)).
   • Work was carried out comparing the values obtained for the end of inflation (φ_end) through direct numerical evolution against the analytical predictions of the slow-roll approximation.

   This is the Colab Notebook containing the results: View on Google Colab.

2. Transition to the Quartic Regime (n = 4): The current focus of the thesis has been reorientated, based on arXiv:2206.08940, towards the analytical and numerical study of the pure quartic regime (n = 4) for inflaton oscillations. This regime is of particular interest because the average equation of state of the universe during the oscillation phase mimics a radiation fluid (⟨w⟩ = 1/3), which fundamentally alters the Hubble expansion rate H(a) and, consequently, the instantaneous rates of gravitational particle production of the spectator field.
3. Development and Injection of Precision Numerical Code: A modular computational environment was designed and implemented in Python, focused on the simultaneous resolution of the coupled set of Friedmann and Klein-Gordon differential equations. The code calculates the time evolution of the scale factor a(t), the inflaton field φ(t), and the energy density functions without relying on explicit couplings.
   
   In the following Colab Notebook, you can review the progress and the work in progress of the "Zero-Coupling" implementation (without initial couplings) as a base case, which, once the stability of the code is validated, will:
   • Introduce the coupling terms.
   • Vary the effective mass parameters.
   • Generate the first occupation spectra.

   View Zero-Coupling Colab Notebook

4. Debugging and Algorithmic Optimisation: Recently, critical computational challenges associated with the numerical stability of the code were resolved. Specifically, inconsistencies originating from the omission of positional arguments within the slow-roll integrand routines were corrected. Even so, the numerical integrator and the graphical results produced by the code continue to be refined.

Academic Meetings and Discussions

Throughout this period, constant meetings have been held with Dr. Marcos Alejandro García García. Recent discussions have focused on the following critical points:

• Transition to the Coupled System: It was established that the next major objective is to integrate the background dynamics, which have already been modelled, with the second field (the spectator field) to evaluate the joint gravitational production.
• Identification of Computational Challenges: The numerical challenges that arise when attempting to couple both fields have been exhaustively discussed, identifying instabilities in the integration methods that require revision.
• Exploration of New Scenarios: The determination and feasibility of studying additional scalar fields to strengthen the phenomenological analysis of the thesis have been proposed.

Programming Projects

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Graduate Written Works & PDFs

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A collection of my academic papers, research reports, and LaTeX thesis drafts.

• Master's Thesis Proposal (PDF)
• Data Visualization Notes (PDF)
• Cosmological Perturbations Literature Review (PDF)

Languages Works

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As a polyglot, I have authored and translated various works across multiple languages. Below is a selection of my linguistic projects.

• English (C2): [INSERT ENGLISH ESSAY/PROJECT]
• Italian (B2): Il mio primo racconto in podcast - Essay and podcast production (1st Place, ENP Interpreparatory Contests 2019)
• German (B1): [INSERT GERMAN ESSAY/PROJECT]
• Portuguese (A2): [INSERT PORTUGUESE ESSAY/PROJECT]