Hitchhiker’s guide to an infinity-free theory

Quantum field theory is the theoretical framework of particle physics. Without it, we never could have worked out what an atom is made of, understood the forces that govern its content, or predicted the Higgs boson.

But when it was first being established in the first half of the 20th century, it came across an apparently fatal flaw. It was plagued with infinities. And infinities don’t belong in physics. Following the rules of quantum field theory, you could end up predicting an electron having an infinite electric charge. Gasp. Its resolution lead to a revolutionised way of thinking that now underpins all of particle physics.

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What’s the Matter with Antimatter?

Why are we here? Ok this is a uselessly vague question; I’ll rephrase. Under what mechanism did the stars, planets, life, and all that come about?

Ask a particle physicist this, and they may be tempted to drag you to the nearest blackboard, write down four lines of maths, and stare at you expectantly as if you’re meant to understand what on earth it means. These four lines represent the standard model of particle physics, which is our most up-to-date attempt to mathematically describe the fundamental constituents of matter, and the forces with which they interact. By matter, I mean what makes up everything around us- planets, stars, life, all composed of atoms, which in turn are composed of smaller particles like electrons and quarks. These are the particles that the standard model governs.


Fig.1: The Standard Model

The standard model has been highly successful at predicting the outcome of experiments, for example in the Large Hadron Collider (LHC) at CERN, and in fact it has withstood basically every test that has been thrown at it. It explains the nature of matter on a very fundamental level. But it’s actually pretty useless at explaining how all that matter got here in the first place.

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