# Superstring theory and renormalization [duplicate]

QED and some quantum theories require renormalization techniques and take it as somehow granted.

I did not study string theories yet, but I would like to whether renormalization similar to QED and some quantum theories is required in superstring theory.

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## marked as duplicate by Qmechanic♦, Sklivvz♦Jan 3 '13 at 13:29

Yes, in peturbative string theory. E.g. vacuum energy. This vacuum energy takes the form of $\frac{\ell_s\hbar}{c_0}\sum_{k=1}^nk$. This has to be renormalised using a Ramanujam sum, and renormalisedd to $-\frac{1}{12}$. However, recently in the past $\approx 20\operatorname{years}$ or so, during the end of the second superstring revolution, there has been an outbreak of something called "matrix models of string theory" which is non-peturbative and there, fore, does not need, clearly, any form, of renormalisation. Examples,: M(Atrix) theory (BFSS Matrix theory), Matrix String theory etc. –  Dimensio1n0 Jun 24 '13 at 10:22