Twistor string theory

Twistor String theory is an equivalence between ${\mathcal {N}}=4$ Supersymmetric Yang-Mills theory and the peturbative Topological B model string theory in twistor space] It was initially proposed by Witten in 2003. This is considered a major breakthrough by many as till Witten's 2003 paper, Twistor theory was only applicable to Classical General Relativity.

Since the dimensionality of Twistor space is necessarily the same as 4-dimensional spacetime with metric signature $\left(-+++\right)$, i.e. 1 time and 3 space, this is also a way to do away with the extra dimensions of string theory.