  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.
