Physics Group Meeting

The goal of this discussion will be to first provide a broader picture and then to discuss the most recent work. I will review the general features of Low energy expansion of stringy amplitudes (tree level and one-loop) and it's relation to number of non-compact dimensions. Then I will show how it is possible to extract low lying terms in string theory low energy expansion from 11 D supergravity on a torus. At last I will discuss the essential features of the very recent work on understanding quantum amplitudes in Horava-Witten theory and it's relation to Heterotic and open string amplitudes.The first two references demonstrates the simplest examples in this direction - both of them discuss four graviton amplitude in theories with 32 supercharges. Since then a huge amount of research has been done in order to understand type II theories and M theory on a torus. The third reference is about the low energy expansion of Heterotic & open string theories in 9 non-compact dimensions and their connection to quantum amplitudes in Horava-Witten theory.References:1. M. B. Green, M. Gutperle and P. Vanhove, “One loop in eleven-dimensions,” Phys. Lett. B 409, 177 (1997) [hep-th/9706175].2. M. B. Green and P. Vanhove, “The Low-energy expansion of
the one loop type II superstring amplitude,” Phys. Rev. D
61, 104011 (2000) [hep-th/9910056].3. M. B. Green and A. Rudra, “Type I/heterotic duality and M-theory amplitudes,” arXiv:1604.00324 [hep-th].