Effect of the twist operator in the D1D5 CFT

TL;DR

This paper analyzes how the twist operator in the D1D5 CFT affects states, providing explicit calculations for vacuum and excited states, which aids in understanding black hole formation via thermalization in the dual gravity theory.

Contribution

It generalizes previous results by computing the twist operator's effects for arbitrary winding numbers, enhancing understanding of state transformations in the D1D5 CFT.

Findings

Computed the squeezed state resulting from the twist operator on the vacuum.

Derived the linear combination of excitations after applying the twist to excited states.

Generalized earlier special-case computations to arbitrary winding numbers.

Abstract

The D1D5 CFT has been very useful in the study of black holes. The interaction in this theory involves a twist operator, which links together different copies of a free CFT. For the bosonic fields, we examine the action of this twist when it links together CFT copies with winding numbers M and N to produce a copy with winding M+N. Starting with the vacuum state generates a squeezed state, which we compute. Starting with an initial excitation on one of the copies gives a linear combination of excitations on the final state, which we also compute. These results generalize earlier computations where these quantities were computed for the special case M=N=1. Our results should help in understanding the thermalization process in the D1D5 CFT, which gives the dual of black hole formation in the bulk.