What is String Theory?
String Theory, sometimes called the Theory of Everything, is thought by some to be the unifying field theory Einstein sought before his death. String theory is the first mathematically sound theory that reconciles the world of the infinitesimally small, with the world we know at large. It unites Einstein’s Theory of Relativity with quantum physics and offers a potential explanation for the Big Bang. Prior to string theory, subatomic particles were envisioned as tiny balls or points of energy. String theory works on the premise that the tiniest subatomic bits that make up the elements of atoms actually behave like vibrating strings. The strings of string theory are so small that physicist Brian Greene has analogized that if a single atom were enlarged to occupy the footprint of our solar system, a string would still be no larger than a tree. Because these tiny vibrating strings are responsible for the properties of all matter, the cosmos has been likened to a cosmic symphony of superstr
Think of a guitar string that has been tuned by stretching the string under tension across the guitar. Depending on how the string is plucked and how much tension is in the string, different musical notes will be created by the string. These musical notes could be said to be excitation modes of that guitar string under tension.
No answer to the question, but he provided an outline of three topics being discussed at the current KITP workshop program that have something to do with it. • String field theory: he wrote down the Witten open-string action and advertised that as the best candidate for a definition of string theory that could go on a t-shirt. He noted some of the problems with this, especially how to understand closed strings, which are somehow “emergent”, “hidden in the measure” on string field space, which one doesn’t really understand. • The Berkovits pure spinor formalism for quantizing the superstring: if you want a consistent theory, you need supersymmetry, and Polchinski explained that the quantization of both supergravity and the superstring are ferociously complicated subjects. He hopes that the Berkovits formalism will provide a more lucid (perturbative) quantization of the superstring, one allowing a proof of finiteness at higher loops. This topic doesn’t really address the “what is string
