Nordita HEP Local Seminars

AdS light-cone strings at one loop.

by Per Sundin (University of Cape Town)

Europe/Stockholm
132:028

132:028

Description
In this seminar I will talk about AdS(p) x M(10-p) string models which occur in various AdS(p) / CFT(p-1)'s. While much is known about the canonical AdS(5) x S(5) string and its close cousin the AdS(4) x CP(3) string, less is known about the less symmetric AdS(3) x S(3) x M(4) and AdS(2) x S(2) x T(6) strings which also appear in AdS / CFT dualities. As it turns out, both models seem to allow for exact solutions using tools from integrability such as spin chains and Bethe equations. In contrast to earlier backgrounds however, a coset construction is not admissible since fermionic degrees of freedom corresponding to broken supersymmetries are part of the physical spectrum. Thus one has to resort to the GS string which nevertheless allow for a rather straight forward construction of the action. We derive the Lagrangians in a BMN-like expansion up to quartic order (but only quadratic in Fermions). We verify that the tree level Bethe equations (up to some minor ambiguities) successfully reproduces the string energies of some simple closed subsectors of the theory. We then compute the one loop corrections to two point functions built out of the bosonic coordinates. For the AdS(3) string these come with three- and four-vertex interactions and different masses. This results in a final answer which seems regularization dependent (very much like the AdS(4) x CP(3) string). Thus the same ambiguities present in AdS(4) / CFT(3) apply also here. I will end the talk with some musing about which regulator is physically motivated.