Having recently investigated the concepts around gravitation (via Special and General Relativity), it’s now time to try to get to grips with Quantum Theory. I’m a Chemist, and the quantum world view is part of my foundational experience (electron quantised energy levels in atoms being the starting point for chemistry). But, I don’t understand it.
I bought and read John Polkinghorne’s Quantum Theory: A Very Short Introduction. I now need to buy another book that introduces the mathematics, and looks at the various consequences of the quantum state of things in more detail. But, my developing understanding of the role of mathematics in physics has received another push along the road of erudition. Here’s where I’m at:
Reality exists in the world (of physics), but we don’t necessarily understand it much (the odd experimental glimpse perhaps). Meanwhile, Pure Mathematicians have been developing all sorts of mathematics (often hundreds of years before), just because they could, and were interested in the maths (no obvious utility at the time). Physicists sometimes realise that a particular mathematics (e.g. Tensors, complex numbers, matrices) might help to describe the physics – they explore this, work out boundary conditions, constraints, and see what pops out. The maths yield possible observable predictions; some of which turn out to be real. Iteration then proceeds, and understanding increases – a new mathematical language emerges which allows reality to be described, explored and investigated. Nobody knew, at the beginning, where this would lead. This is part of the excitement of Physics.
Quantum Theory, then. Boy, bizarre and counter-intuitive. One of my favourite findings (to date) is that combining Quantum Theory and Special Relativity yields the concept of anti-matter! And, that a vacuum is actually a humming hive of activity (although there is nothing there).