Review: Professor Nick Evans

Photo by Milo Brooks (B1 U6)

Category: General, Academic, Speakers

On Friday 29th September Marlborough was delighted to welcome Professor Nick Evans from the University of Southampton for a Science Department Talk. He is Professor of Theoretical Physics, with particular research interests in quantum gravity and the strong nuclear force beyond the standard model.

Professor Evans spoke about the history and the physics of ‘nothing’, scientifically redefined as a vacuum. He began by outlining how the concept of something within nothing came about, and how the modern definition of a vacuum is a point with the lowest energy density. This is an interesting concept as by existing, a vacuum isn’t actually nothing, but is something, and something quite complicated. Various theories have come about over time, starting from Indian Philosophy, stating that we start from nothing and hence should return to nothing (Nirvana), indicating that the overall energy of the soul should remain constant. Later on, with the increasing popularity and acceptance of science, the concept of a vacuum turned into that where there was no matter.

This was questioned by the establishment of the concept of waves, as light displayed the unusual property of being able to travel through a vacuum. It was first proposed that there must be some form of medium for light to propagate through, which was named the ‘luminiferous aether’. The existence of the aether was disproved in a famous attempt to prove it by the Michelson-Morley experiment, which is the basic idea behind modern gravitational wave interferometers. Further progress required delving into Einstein's theories of Special and General Relativity, leading to the birth of Quantum Mechanics, more popularly known as the counterintuitive part of particle physics.

Professor Evans concluded the evening by talking about how the fluctuations in energy density within a vacuum are favourable for the formation of quark and antiquark pairs, which is a result of the strong nuclear force attempting to lower the overall energy. This has a fundamental link to the Higgs Boson (aka ‘the God particle’) making it the carrier particle for mass and determining what is affected by the force field created by it. Interestingly, Professor Evans finished by highlighting one of the major issues in theoretical physics today, which is that according to current quantum gravity theories, the universe should be the size of a grapefruit, making predictions that are out by forty orders of magnitude!

Simran Chowdhry (LI U6)

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