Found 2 result(s)

12.05.2016 (Thursday)

One-point Functions of AdS/dCFT from Matrix Product States

Regular Seminar Charlotte Kristjansen (NBI)

14:00 QMW
room G.O. Jones 610

One-point functions of certain non-protected scalar operators in the defect CFT dual to the D3-D5 probe brane system with k units of world volume flux can be expressed as overlaps between Bethe eigenstates of the Heisenberg spin chain and a matrix product state. We present a closed expression of determinant form for these one-point functions, valid for any value of k. The determinant formula factorizes into the k=2 result times a k-dependent prefactor. Making use of the transfer matrix of the Heisenberg spin chain we recursively relate the matrix product state for higher even and odd k to the matrix product state for k=2 and k=3 respectively. We furthermore find evidence that the matrix product states for k=2 and k=3 are related via a ratio of Baxter's Q-operators. The general k formula has an interesting thermodynamical limit involving a non-trivial scaling of k, which indicates that the match between string and field theory one-point functions found for chiral primaries might be tested for non-protected operators as well. We revisit the string computation for chiral primaries and discuss how it can be extended to non-protected operators.

25.02.2009 (Wednesday)

Non-planar ABJM Theory, Integrability and Parity

Triangular Seminar Charlotte Kristjansen (NBI)

16:00 QMW
room PLT

First we review existing results concerning the non-planar spectrum of N=4 SYM. Next, using an effective vertex method we explicitly derive the two-loop dilatation generator of ABJM theory in its SU(2) x SU(2) sector, including all non-planar corrections. This generator is then applied to a series of finite length operators as well as to two different types of BMN operators. As in N=4 SYM, at the planar level the finite length operators are found to exhibit a degeneracy between certain pairs of operators with opposite parity -- a degeneracy which can be attributed to the existence of an extra conserved charge and thus to the integrability of the planar theory.When non-planar corrections are taken into account the degeneracies between parity pairs disappear hinting the absence of higher conserved charges. The analysis of the BMN operators resembles that of N=4 SYM. Additional non-planar terms appear for BMN operators of finite length but once the strict BMN limit is taken these terms disappear.