Probably Physics

Alexei Gilchrist

Exploration of the role of probability in various areas of physics

Probability permeates much of physics. It appears in quantifying errors in every measurement, in the dynamics of stochastic processes, in statistical mechanics as a way of coping with the vast amount of variables, and even intrinsically in quantum mechanics. At first glance the use of probability may seem natural and even `obvious’, but things get much more lively when you realise that it is still not settled what a probability is. Different interpretations of probability affect the meaning of all the areas that it touches.

This material supports a second and third year advanced physics unit at Macquarie University.

In these notes I will take the view that probabilities are a measure of plausibility and probability theory is the extension of deductive logic to incomplete information. This view follows Laplace, Jeffreys, Cox, and Jaynes.

Status: In development. These notes are very much a work in progress and an exploration of the topic. They may change radically in the future. Lecture notes are available as mindmaps here: /map/probably-physics/.

© Copyright 2021 Alexei Gilchrist