Ramond States of the D1-D5 CFT away from the free orbifold point

TL;DR

This paper investigates how deforming the D1-D5 CFT away from the free orbifold point affects Ramond ground states, revealing protected states and anomalous dimensions through four-point function analysis.

Contribution

It provides a detailed computation of the effects of a marginal deformation on twisted Ramond states, including conformal dimensions and structure constants, advancing understanding of the CFT's moduli space.

Findings

Single-cycle Ramond fields are renormalized.

Multi-cycle ground states remain protected at leading order.

Deformation operator's OPEs with Ramond fields are characterized.

Abstract

The free orbifold point of the D1-D5 CFT must be deformed with a scalar marginal operator driving it to the region in moduli space where the holographic supergravity description of fuzzball microstates becomes available. We discuss the effects of the deformation operator on the twisted Ramond ground states of the CFT by computing four-point functions. One can thus extract the OPEs of the deformation operator with these Ramond fields to find the conformal dimensions of intermediate non-BPS states and the relevant structure constants. We also compute the anomalous dimensions at second order in perturbation theory, and find that individual single-cycle Ramond fields are renormalized, while the full multi-cycle ground states of the $S_N$ orbifold remain protected at leading order in the large-$N$ expansion.