Microstates at the boundary of AdS

Understand

The bound states of the D1D5 brane system have a known gravitational description: flat asymptotics, an anti-de Sitter region, and a 'cap' ending the AdS region.

• We construct perturbations that correspond to the action of chiral algebra generators on Ramond ground states of D1D5 branes.
• Abstract arguments in the literature suggest that the perturbation should be pure gauge in the AdS region; our perturbation indeed has this structure, with the nontrivial deformation of the geometry occurring at the 'neck' between the AdS region and asymptotic infinity.
• This 'non-gauge' deformation is needed to provide the nonzero energy and momentum carried by the perturbation.