WILL CERNE
Researcher - Theoretical Cosmology - Inflation
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About Me
Welcome to my page. I am Will Cerne, an M2 student in theoretical cosmology at the Institute of Science Tokyo. I am a part of the Suyama Research Lab. My current research focuses on inflation, although in the future I would like to work on many areas of cosmology.
I was raised in Wisconsin, USA. I did my undergraduate work at the University of Wisconsin-Madison, with Moritz Muenchmeyer as my research advisor. In March of 2024, I moved to Japan to pursue my doctorate at the Institute of Science Tokyo (formerly Tokyo Institute of Technology).
My hobbies outside of physics include learning Japanese and competitive Rubik's Cube solving. I am in the top 50 fastest solvers in the Rubik's Cube Blindfolded category, with a peak world ranking of 19th.
If you are interested in talking with me about my research, please contact me at cerne.w.57e6@m.isct.ac.jp
Research Interests
My research focuses on cosmic inflation and the quantum dynamics of fields in the early Universe, with particular emphasis on cosmological perturbations generated during inflation.
My current work studies the effective action of the inflaton field beyond leading order in the slow-roll expansion. By decomposing the scalar field into a spatially averaged mean field and fluctuations about this background, I compute the one-particle-irreducible effective action obtained by integrating out the fluctuation field. Varying this effective action yields an equation of motion for the quantum expectation value of the inflaton that consistently incorporates its self-interaction with quantum fluctuations.
This formalism generates new terms that appear at second order in slow-roll inflation. I am interested in understanding the physical interpretation and dynamical consequences of these corrections, as well as their role in stochastic and non-local effects during inflation. My recent work (arXiv:2601.22644) develops this framework in the exact de Sitter background, treating the inflaton as a test field and isolating the structure of the induced drift, noise, and memory terms.
A central goal of this research is to extend this approach to include cosmological perturbations and metric fluctuations and to investigate how these quantum corrections may modify inflationary observables such as scalar metric perturbations and the curvature perturbation power spectrum.
Feel free to contact me at cerne.w.57e6@m.isct.ac.jp with inquiries about my research!
Published Works
Cerne, W. and Suyama, T. Non-local corrections to the effective action of a scalar field in de Sitter spacetime, arXiv:2601.22644 (2026).
Presentations
February 2026: Intensive lecture course on inflation by Prof. Misao Sasaki - Contributed Talk
I gave a contributed talk at the event hosted at Kavli IPMU February 9-10, 2026.
March 2025: JGRC 2025 - Poster Presentation - The Inflaton Effective Action: Novel Terms
I did a poster presentation at JGRC 2025 about my ongoing research in the inflaton effective action.
Education
September 2020 - December 2023: University of Wisconsin-Madison
Bachelor's of Science in Mathematics, Bachelor's of Science in Physics, Certificate of Professional Japanese Communication
April 2024 - present: Institute of Science Tokyo
Master of Science in Physics
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