Found 2 result(s)

29.03.2017 (Wednesday)

Yang-Baxter strings, twists, and AdS/CFT

Regular Seminar Stijn van Tongeren (Humboldt U.)

at:
14:00 IC
room H503
abstract:

The appearance of integrability in the duality between the AdS5xS5 string and planar maximally supersymmetric Yang-Mills theory gives rise to many insightful results. Various deformations of this AdS/CFT dual pair are known to also be integrable, prompting the question how far the power of integrability extends in this setting. In recent years there has been a lot of progress in answering this question. Rather than trying to demonstrate integrability in known AdS/CFT dual pairs, efforts instead focused on finding manifestly integrability preserving deformations of the AdS5xS5 string. While constructed to preserve integrability, the resulting so-called Yang-Baxter sigma models are, however, not guaranteed to describe strings, or have an AdS/CFT interpretation. The former of these points has since been addressed and turns out to be closely related to (nonabelian) T duality, and we now understand which of these models continue to describe strings. The goal of my talk is to address the latter point, regarding the AdS/CFT interpretation of these models. I will use symmetry considerations to give a unified AdS/CFT picture for these Yang-Baxter strings as duals to various noncommutative deformations of supersymmetric Yang-Mills theory. My general conjecture matches many known dualities, and I will briefly discuss nontrivial tests in various new cases, in the form of brane constructions indicating the desired dualities.

07.11.2012 (Wednesday)

The AdS5xS5 string spectrum, Pohlmeyer reduction and quantum deformations

Regular Seminar Stijn van Tongeren (ITP and Spinoza Inst., Utrecht)

at:
14:00 IC
room H503
abstract:

In the setting of integrability in AdS/CFT, in the typical approach to the AdS_5 x S^5 string a light-cone gauge is fixed, breaking Lorentz invariance on the worldsheet. One attempt to avoid the need for this goes under the name of Pohlmeyer reduction. Recently an S-matrix was conjectured to describe the scattering of solitons in this theory. Now as I will explain in my talk, the S-matrix of an integrable quantum field theory together with its dispersion relation are enough to find its finite volume spectrum exactly, through the so-called thermodynamic Bethe ansatz. I will work this out for an S-matrix and dispersion that interpolate between the standard light-cone gauge fixed superstring and this conjectured Pohlmeyer S-matrix, by analogy to a simpler model. Viewed as a deformation of the light-cone gauge fixed superstring TBA, this story is very similar to deforming the XXX spin chain to the XXZ one, which I will concretely discuss. I will finish by emphasizing important differences to this simple toy model, and discuss surprises in the so-called Y-system associated to the TBA equations.