World-Sheet

I have found some free time lately. The best way to relax is to read some String Theory. I have the textbook A First Course in String Theory by Barton Zwiebach. This book is so easy to read. Someone with some background in Lagrangian Dynamics and Relativity can read it and take lots of things out. I am up to chapter 6 on Relativistic Strings.

Basically point particles trace out a curve in spacetime called a world-line. The action of the particle can be written in terms of a line element. Since strings are one dimensional objects, the classical action of a string can be written in terms of the proper area of the surface they trace in spacetime. This surface is called the world-sheet. The classical relativistic string action is called the Nambu-Goto String Action.

It is so cool to learn about this. The only thing that I find scary is a bit of lack of motivation. I guess real motivations will come when one meet QCD and its shortcomings.