The First Thing You'll Learn in a String Theory Class
This video is part 4 of the series I've been sharing with you about the principle of least action. The first video was about a particle in Newtonian mechanics, the second was about a particle in special relativity, and the third about a particle in general relativity.
In this video, we'll learn about the principle of least action for string theory. It's called the Nambu-Goto action, and it's given by the area of the worldsheet that the string sweeps out as it moves through spacetime.