Trevor Cheung’s academic page

Publications:

• Massive spinning fields during inflation: Feynman rules and comparison
  Preprint: arXiv:2509.08888, Journal: JCAP 05 (2026) 022, Inspire HEP page
  We investigated whether the two setups (dubbed cosmological collider (CC) and cosmological condensed matter (CCM)) describing massive spinning fields during inflation actually give different cosmological correlators, and corrected the Feynman rules in the literature for such computations.

  Associated PPT for talks: UK QFT 2025, Inflation 2025

Other academic / physics related documents:

• Massive spinning fields during inflation PPT (Last edit: 28/5/2026)

  A PPT for talk when “touring” around East Asian institutes. Involving my second project on using microcausality to constrain the most general EFT for massive spin-1 fields during inflation. GeoGebra files can be downloaded here.

• Are Feynman rules you learnt correct? (Part II) (Last edit: 1/10/2025)

  The sequel to the previous one: last time it dealt with derivative interactions, but this time it deals with constrained fields, in particular massive Proca field. Similar but also different story than the last one.

• Cosmological correlators with massive spinning fields talk PPT (Last edit: 21/3/2025)

  A PPT for talk on my first PhD project on cosmological correlators that involve a massive spinning field exchange. The GeoGebra file (for inflaton slices) can be downloaded here.

• A subtle point on Feynman rules (Last edit: 23/10/2024)

  The Feynman rules you’ve learnt in a QFT course are correct and not correct at the same time, in the sense that they give the right result, but technically you made two mistakes that cancel each other.

• The first year talk I give in a student journal club

  A talk on my research progress in my first year.

• The wavefunction formalism for computing cosmological correlators (Last edit: 27/11/2023)

  For first-time learners (especially those who want to do the actual calculations) of cosmological correlators. This has certain advantage over the alternative in-in or Schwinger-Keldysh formalism.

• The essay written for Cambridge Part III (masters)

  On the topic of preheating, the period right after inflation but before reheating (the final transition to a thermal Big Bang, creating all particles we see today). It is purely a literature review as we were not expected to conduct research in masters degree.

• Talk on Optical Theorem

  On the topic of (generalised) optical theorem in quantum field theory, an instance of showing how strong unitarity poses a constraint. However, an important note would have been on renormalisation (which I was not too confident on at the time).

Miscellaneous:

• Two integrals Heidelberg Integration Bee (HIB, 2024) used

  The HIB committee asked me to submit integrals for the competition, and I ended up submitting 6. These two were the ones they used for the 2024 competition (with solutions).

• A more popular science approach to the maths of GR

  A slightly deeper look into the maths of GR (differential geometry) - this is written for a much more general audience, so expect this to be oversimplified.

• My student talk at the Archimedeans

  On a research project I did at age 17 on generalisations of triangle centres to tetrahedra (which could be further generalised to simplices). Too proud of the project to let it go, I decided to give a student talk when given the chance.

• My curated set of interview questions for Cambridge maths (+ maths with physics) admissions

  For prospective students to Cambridge maths (or maths with physics) programme to practice. Deliberately does not give any “model answers” because the point of the interview is to see how you think.