`Found 3 result(s)`

Journal Club Charlotte Kristjansen (Niels Bohr Institute Copenhagen)

at:15:15
room Zoom, instructions in abstract | abstract: The $\mathfrak{psu}(2,2|4)$ integrable super spin chain underlying the AdS/CFT correspondence has integrable boundary states which describe set-ups where $k$ D3-branes get dissolved in a probe D5-brane. Overlaps between Bethe eigenstates and these boundary states encode the one-point functions of conformal operators and are expressed in terms of the superdeterminant of the Gaudin matrix that in turn depends on the Dynkin diagram of the symmetry algebra. The different possible Dynkin diagrams of super Lie algebras are related via fermionic dualities and we determine how overlap formulae transform under these dualities. As an application we show how to consistently move between overlap formulae obtained for $k=1$ from different Dynkin diagrams. -------------------- Part of the London Integrability Journal Club. New participants please register using the form at integrability-london.weebly.com. |

Regular Seminar Charlotte Kristjansen (NBI)

at:14:00
room G.O. Jones 610 | abstract: 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. |

Triangular Seminar Charlotte Kristjansen (NBI)

at:16:00
room PLT | abstract: 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. |