Description
In this talk, we present the nonrelativistic limit of IIB supergravity at the level of action. This limit is based on reparameterizing the background fields of type IIB superstring theory. Recently, it was shown that the cancellation of the divergencies between Einstein-Hilbert and the Kalb-Ramond term in the NS-NS sector is based on the critical limit. In addition to this, we show that taking the limit of the action leads to additional divergent terms in the RR sector. However, these extra terms can be written as two terms without a leading divergence upon introducing an auxiliary field. After taking the limit, the auxiliary field becomes a Lagrange multiplier imposing a constraint on some RR fluxes. Interestingly, the equation of motion of the Lagrange multiplier is precisely one of the self-duality conditions resulting from the non-relativistic limit of the relativistic condition. We then show that the action is invariant under boosts, gauge symmetries, dilatations, and SL(2,R) transformations. In particular, we will argue that these symmetries uniquely fix the nonrelativistic IIB action.
