Birth of Strings: String Theory Explained

[clerk]

I am sorry if this sounds too philosophical but thanks for any inputs ..

String theory claims that every particle in this universe is actually a manifestation of vibrations of fundamental strings. But how do these strings came into existence in the first place ? I understand the concept of stringy vibrations producing particles but what are these strings made up of ? Are they purely theoretical constructs ?

 

[tom.stoer]

... but what are these strings made up of ? Are they purely theoretical constructs ?

Yes.

We use a mathematical formalism to describe nature, that means we must be able to extract physical content, experiments, predictions for measurable quantities (which does not work well with strings ;-) But we cannot say what these mathematical entities "are made of".

Look at ordinary general relativity: the fundamental entity is a four-dim. manifold which we call spacetime. The mathematical formalism tells us that the manifold can be curved in quite complex ways. We can associate this curvature to measurable effects (gravitation, gravitational waves, the expanding universe, ...). But we cannot answer the question "what this manifold is made of".

What we can do is to try to find more fundamental descriptions like string theory as a fundamental theory underlying general relativity (and other theories). If this approach is successful we can explain to some extent how the macroscopic spacetime manifold emerges from the microscopic strings, so in some sense we can answer the question for spacetime (but to be honest, I don't see that string theory already provides an answer to this question; I would not call it a theory but a hypothesis, or a "theory under construction"; so we cannot claim to be able to answer the question for spacetime using strings; and of course we cannot answer the question for strings themselves, either)

 

[Korybut]

In string theory strings are fundamental, just electron or photon in SM