Unification of Decoupling Limits in String and M Theory

We study and extend the duality web unifying different decoupling limits of type II superstring theories and M theory. We systematically build connections to different corners, such as matrix theories, nonrelativistic string and M theory, tensionless (and ambitwistor) string theory, Carrollian string theory, and spin matrix limits of AdS/CFT. We discuss target space, world sheet, and worldvolume aspects of these limits in arbitrary curved backgrounds.

Figure 1

The duality web of decoupling limits. Here, DLCQ is short for the procedure of compactifying the theory over a lightlike circle followed by a T duality. In the web, these lightlike circles become spacelike in their T-dual theories.