Triangle Seminars
Wednesday, 8 Feb 2017
Integrable quantum field theories and von Neumann algebras
📍 London
Gandalf Lechner
(Cardiff University)
Abstract:
In this talk, I will report on a research programme that addresses the problem of constructing integrable relativistic quantum field theories on two-dimensional Minkowski space from their two-body S-matrix. The aims of this programme are thus identical to the form factor programme, but the tools are different: Instead of concentrating on a perturbative construction of the correlation functions of local fields, we construct a pair of "semi-local" quantum fields and use operator-algebraic tools to study local fields/observables. This leads to a construction of many models, including the Sinh-Gordon model. As another prominent example, I will also report on the status of the O(N) sigma models within this setting.
In this talk, I will report on a research programme that addresses the problem of constructing integrable relativistic quantum field theories on two-dimensional Minkowski space from their two-body S-matrix. The aims of this programme are thus identical to the form factor programme, but the tools are different: Instead of concentrating on a perturbative construction of the correlation functions of local fields, we construct a pair of "semi-local" quantum fields and use operator-algebraic tools to study local fields/observables. This leads to a construction of many models, including the Sinh-Gordon model. As another prominent example, I will also report on the status of the O(N) sigma models within this setting.
Posted by: KCL
Semiclassics, Goldstone Bosons and CFT data
Alexander Monin
(Ecole Polytechnique, Lausanne)
Abstract:
In a generic CFT the spectrum of operators carrying a large U(1) charge can be analyzed semiclassically in an expansion in inverse powers of the charge. The key is the operator state correspondence by which such operators are associated with a finite density superfluid phase for the theory quantized on the cylinder. The dynamics is dominated by the corresponding Goldstone hydrodynamic mode and the derivative expansion coincides with the inverse charge expansion. I will illustrate this situation by first considering simple quantum mechanical analogues and then will systematize the approach by employing the coset construction for non-linearly realized space-time symmetries. Focussing on CFT3 I will illustrate that the three point function coefficients turn out to satisfy universal scaling laws and correlations as the charge and spin are varied.
In a generic CFT the spectrum of operators carrying a large U(1) charge can be analyzed semiclassically in an expansion in inverse powers of the charge. The key is the operator state correspondence by which such operators are associated with a finite density superfluid phase for the theory quantized on the cylinder. The dynamics is dominated by the corresponding Goldstone hydrodynamic mode and the derivative expansion coincides with the inverse charge expansion. I will illustrate this situation by first considering simple quantum mechanical analogues and then will systematize the approach by employing the coset construction for non-linearly realized space-time symmetries. Focussing on CFT3 I will illustrate that the three point function coefficients turn out to satisfy universal scaling laws and correlations as the charge and spin are varied.
Posted by: IC
Thursday, 9 Feb 2017
Generalized type II supergravity from kappa symmetry
Linus Wulff
(Imperial)
Abstract:
It has been known since the 80's that the Green-Schwarz superstring possesses the fermionic kappa symmetry, required for the consistency of the formulation, if the target space is a solution of the supergravity equations of motion. However, contrary to the standard lore and previous claims in the literature, it was recently shown that the converse is not true. Kappa symmetry of the Green-Schwarz superstring implies only a weaker set of equations for the target space fields, which we refer to as generalized supergravity equations. I will describe these equations for the type II case and contrast them with the standard type II supergravity equations which arise as a special case.
It has been known since the 80's that the Green-Schwarz superstring possesses the fermionic kappa symmetry, required for the consistency of the formulation, if the target space is a solution of the supergravity equations of motion. However, contrary to the standard lore and previous claims in the literature, it was recently shown that the converse is not true. Kappa symmetry of the Green-Schwarz superstring implies only a weaker set of equations for the target space fields, which we refer to as generalized supergravity equations. I will describe these equations for the type II case and contrast them with the standard type II supergravity equations which arise as a special case.
Posted by: QMW