# Past Events — Lent 2020

*Unless otherwise stated, the talks are held at 7pm in MR2 at the Centre for Mathematical Sciences (the CMS), Wilberforce Road.*

### 17th January 2020 — Prof. Alain Goriely (University of Oxford)

#### Does maths matter to brain matter? The curious geometry of the brain

The fascinating convolutions of the human brain are believed to be caused by mechanical forces generated in the rapid expansion of the cortex with respect to the subcortical areas of the brain. These intricate folded shapes have fascinated generations of scientists and mathematicians and have, so far, defied a complete description. How do they emerge? How are they arranged? How is the brain shape related to its function? In this talk, I will review our current understanding of brain morphogenesis and how it can be modelled. In particular, I will discuss an ideal version of this problem that can be solved exactly, underlying the beautiful interplay between (differential) geometry and mechanics in the shaping of our most intricate organ.

### 24th January 2020 — Prof. Nick Dorey (University of Cambridge)

#### What is quantum field theory?

Quantum field theory (QFT) has been very successful in describing nature, in some cases yielding the most precise agreement between experiment and theory ever achieved. It underlies our current understanding of high energy physics, cosmology and condensed matter physics. Despite this, the theory does not have a satisfactory first-principles definition. Even its most accurate predictions mentioned above, come from summing the first few terms of series which is ultimately divergent. I will review this problem and also review various ways in which QFT has influenced (and been influenced by) different areas of mathematics.

### 31st January 2020 — Prof. Herbert Huppert (University of Cambridge)

#### Dimensional Analysis: How to get something for (nearly) nothing

Physicists and mathematicians frequently encounter difficult, often nonlinear, problems. Often dimensional analysis can be employed to find either the correct answer directly or explain the main aspects of the solution. The talk will develop the mathematical background and then apply these to a number of situations including: a simple proof of Pythagoras’ theorem, the speed of animals running up hill, the speed of a boat with N oarsmen (N = 1, 2, 4, 8, …); how to judge weightlifting and other pursuits accurately without having to have classes of different weight, the rate of spread of an atomic eruption, …