Momentum fractionation on superstrata

Iosif Bena,Nicholas P. Warner,Emil Martinec,David Turton

doi:10.1007/jhep05(2016)064

Abstract

Superstrata are bound states in string theory that carry D1, D5, and momentum charges, and whose supergravity descriptions are parameterized by arbitrary functions of (at least) two variables. In the D1-D5 CFT, typical three-charge states reside in high-degree twisted sectors, and their momentum charge is carried by modes that individually have fractional momentum. Understanding this momentum fractionation holographically is crucial for understanding typical black-hole microstates in this system. We use solution-generating techniques to add momentum to a multi-wound supertube and thereby construct the first examples of asymptotically-flat superstrata. The resulting supergravity solutions are horizonless and smooth up to well-understood orbifold singularities. Upon taking the AdS3 decoupling limit, our solutions are dual to CFT states with momentum fractionation. We give a precise proposal for these dual CFT states. Our construction establishes the very nontrivial fact that large classes of CFT states with momentum fractionation can be realized in the bulk as smooth horizonless supergravity solutions.

Highlights

String theory has been successful in counting the microstates of black holes in the regime of parameters where stringy effects overwhelm gravitational effects at the horizon scale
There are a range of “sub-possibilities”: at one extreme, typical black-hole microstates would not be describable in supergravity, but will be intrinsically quantum or non-geometrical; at the other extreme, in the sector dual to the typical microstates, one could find a basis of Hilbert space vectors that correspond to coherent states that have a supergravity description, or at least a stringy limit thereof
Summary of proposed dual CFT states. In both Style 1 and Style 2, we start with a two-charge seed solution, determined by a profile function

Summary

Introduction

String theory has been successful in counting the microstates of black holes in the regime of parameters where stringy effects overwhelm gravitational effects at the horizon scale. Very little is known about the fate of the individual stringy microstates, counted in the zero-gravity regime, as one increases the gravitational coupling and goes to the regime in which the configuration corresponds to a classical black hole with a large event horizon. As gravity becomes stronger, all these microstates develop a horizon and end up looking identical to the black hole [8,9,10]. Another is that some of the microstates that one constructs at zero gravitational coupling will develop a horizon, and others will remain horizonless. There are a range of “sub-possibilities”: at one extreme, typical black-hole microstates would not be describable in supergravity, but will be intrinsically quantum or non-geometrical; at the other extreme, in the sector dual to the typical microstates, one could find a basis of Hilbert space vectors that correspond to coherent states that have a supergravity description, or at least a stringy limit thereof

Objectives

Discussion

Conclusion