Photo of me

Alexander Farren

About me

2025-2029: PhD in Theoretical Physics at Cambridge.
2024-2025: MASt in Mathematics at Cambridge.
2020-2024: BA in Theoretical Physics at Trinity College, Dublin.

Doing a PhD in theoretical cosmology. Hoping to learn how quantum field theory worked at the beginning of the Universe!

Alexander Farren

amf94@cam.ac.uk·INSPIRE

Photo of me

About me

2025-2029: PhD in Theoretical Physics at Cambridge.
2024-2025: MASt in Mathematics at Cambridge.
2020-2024: BA in Theoretical Physics at Trinity College, Dublin.

Doing a PhD in theoretical cosmology. Hoping to learn how quantum field theory worked at the beginning of the Universe!
Visualisations

A cloud chamber reveals charged particles which are usually invisible to the naked eye. These basic experiments played a historical role in our understanding of particle physics, and can be made at home with a bit of effort! I created this interactive webpage as a convenient version of the real thing, where you can add radioactive sources and choose which particles to observe.

Animated plot of three solitary waves of different heights moving at different speeds
Learned about basic soliton theory with Eliza Somerville and wrote a short introduction to solitons in 1+1 dimensions, namely solutions to the KdV equation and kink solitons for a \(\small\phi^4\) potential and a sine-Gordon potential. Here you will find some satisfying animations.

Following an independent reading project on statistical field theory, my interest in critical behaviour led to this visual showcase of the square lattice Potts model. To play around with the lattice, see the interactive gallery (best on desktop).
Research

Part III Essay – 2025

Diagram of fermions scattering off a magnetic monopole, coming in as one species and leaving as another
In my essay I discussed what happens when one scatters a fermion off a magnetic monopole—a story dating back to the 70's. After solving the Dirac equation in the presence of a monopole, it turns out the lowest angular momentum mode of fermions exhibits the peculiar behaviour of states being split into either in or out, such that quantum numbers like chirality and electric charge are violated. Strange consequences arise when combining this effect with GUTs. My essay setter was Prof. David Tong.
Essay

Bachelor Thesis – 2023/2024

Sketch of a string worldsheet in AdS5 x S5
My thesis was a review of Foundations of the \(\small\text{AdS}_5\times S^5\) Superstring in which I reproduced many of the results from the first two chapters. It involved learning about basic string theory, superalgebras, the Green-Schwarz superstring in \(\small\text{AdS}_5\times S^5\), and how one could go about quantising it in the light-cone gauge. It turns out to be difficult to quantise the model directly so one resorts to a perturbative approach in the limit as the string length goes to infinity. My supervisor was Prof. Sergey Frolov.
Thesis Slides Poster
Talks

Part III Seminar – Dec 2024

Cartoon of a figure made of gluon lines standing on a turtle shell, next to a wave
I enjoyed learning about the on-shell bootstrap techniques for tree-level amplitudes from Cliff Cheung's TASI lectures, so I decided to prepare a student seminar for my master's cohort on the Parke-Taylor formula and loop amplitudes.
Slides
Miscellaneous

MathDeriver – Oct 2024

Logo of the Flywheel hackathon: a flywheel
As part of the 1-day Flywheel: Tools for Science hackathon event, I collaborated with Joe Bacchus George and Piotr Toka to create a python script capabale of providing users with the derivation of numbered equations from arXiv articles. (Oct 2026 update: this is now completely obsolete!)
Github

Rocket Launch – Jan 2024

Four people standing in a field next to a model rocket
Built a simple model rocket, Puffin 1, with the Rocketry Comittee of the Trinity Space Society. Some wind led to the launch going sideways... Pictured are myself, Nathan Besch, Grace Madison and Oskar García García de las Heras.
Trinity News article Video of launch