# Background independent string theory

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I don't really understand what one actually means when one says about doing string theory in a background independent way.

Apparently B. Sathiapalan is the only person (as far as I know from literature searching) who has been looking into it from a long time. Here is a very recent review by Sathiapalan. The introduction and conclusions of it look very nicely written.

Can someone discuss in detail where actually does the problem of background independence occur in string theory and the progress so far in this direction.

This post imported from StackExchange Physics at 2015-09-10 17:15 (UTC), posted by SE-user pinu
I hope you get a proper answer, but to me, crudely, it means it cannot currently be incorporated into general relativity, as any overall theory of quantum gravity should apply "everywhere". I will delete this comment if it's incorrect.

This post imported from StackExchange Physics at 2015-09-10 17:15 (UTC), posted by SE-user Acid Jazz
Background independence usually means that one does not start with a pre-existing notion of coordinate space, i.e. there is no pre-defined metric structure that exists before and independently of any definition of an actual physical dynamics. I am not aware of a successful example of a background independent theory, not even in case of a toy model of physics. I would also be careful to call metric-free theories that start with some sort of topology (like a "worldsheet") background independent. As long as you see coordinate functions used, you are not truly background independent.

This post imported from StackExchange Physics at 2015-09-10 17:15 (UTC), posted by SE-user CuriousOne

Is this theory, MetaString in the right direction of background independence?

http://arxiv.org/abs/1502.08005

I must confess that I only read the abstract, but they say:"... we have introduced a reformulation of string theory which does not rely on an {\it a priori} space-time interpretation or a pre-assumption of locality."

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