Bubbling 1/4 BPS solutions in type IIB and supergravity reductions on S^n x S^n

TL;DR

This paper explores the construction of bubbling 1/2 BPS and 1/4 BPS solutions in type IIB supergravity and 6d supergravity reductions, revealing constraints and extending known solutions with new fields like the axion-dilaton.

Contribution

It demonstrates the limitations of 6d supergravity reductions for bubbling solutions and introduces 1/4 BPS solutions with back-reacted D7 branes in type IIB.

Findings

Consistent 6d supergravity reduction requires a F∧F=0 constraint.

Constructed 1/2 BPS solutions in 6d supergravity under this constraint.

Developed 1/4 BPS solutions in type IIB with axion-dilaton and D7 branes.

Abstract

We extend the construction of bubbling 1/2 BPS solutions of Lin, Lunin and Maldacena (hep-th/0409174) in two directions. First we enquire whether bubbling 1/2 BPS solutions can be constructed in minimal 6d supergravity and second we construct solutions that are 1/4 BPS in type IIB. We find that the S^1 x S^1 bosonic reduction of (1,0) 6d supergravity to 4d gravity coupled to 2 scalars and a gauge field is consistent only provided that the gauge field obeys a constraint (F \wedge F=0). This is to be contrasted to the case of the S^3 x S^3 bosonic reduction of type IIB supergravity to 4d gravity, 2 scalars and a gauge field, where consistency is achieved without imposing any such constraints. Therefore, in the case of (1,0) 6d supergravity we are able to construct 1/2 BPS solutions, similar to those derived in type IIB, provided that this additional constraint is satisfied. This ultimately prohibits the construction of a family of 1/2 BPS solutions corresponding to a bubbling AdS_3 x S^3 geometry. Returning to type IIB solutions, by turning on an axion-dilaton field we construct a family of bubbling 1/4 BPS solutions. This corresponds to the inclusion of back-reacted D7 branes to the solutions of Lin, Lunin and Maldacena.