Associate Professor, Theoretical Particle Physics.
Sep 16, 2023 • 16 tweets • 6 min read
What is the transpose of a (1,1) tensor?
If we define a matrix to be an array of numbers, the transpose flips the array along the diagonal.
Apr 20, 2023 • 15 tweets • 5 min read
Let's talk about the Planck mass. Here is the action for four-dimensional gravity coupled to matter.
Varying the action with respect to the metric gives the Einstein field equations. Classically, the overall normalization of the action does not matter: it would amount to multiplying both sides by the same constant.