Triangle Seminars
Wednesday, 22 Mar 2017
Resurgence in Large N Gauge and String Theory
📍 London
Ricardo Schiappa
(Lisbon University)
Abstract:
I will present a light introduction to resurgence, with applications in large N gauge theory and in string theory.
I will present a light introduction to resurgence, with applications in large N gauge theory and in string theory.
Posted by: KCL
Polygon Seminar: Tree-level scattering amplitudes with the pure spinor formalism
📍 London
Carlos Mafra
(U. Southampton)
Abstract:
I will give a pedagogical review of how the pure spinor formalism was used to obtain all tree-level amplitudes of the superstring, including all their alpha' corrections.
I will give a pedagogical review of how the pure spinor formalism was used to obtain all tree-level amplitudes of the superstring, including all their alpha' corrections.
Posted by: KCL
Thursday, 23 Mar 2017
The a-function in 3 dimensions
Ian Jack
(Liverpool)
Abstract:
The a-theorem expressing the monotonicity of renormalisation group flows in four (and other even) dimensions is now well-accepted. There is a function (the a-function) generating the RG beta-functions as a gradient flow via a positive-definite metric. However the standard definition of the a-function in terms of the trace anomaly of the energy-momentum tensor does not work in odd dimensions. In this talk we focus on the gradient-flow property of the a-function and show that a function with similar properties can be constructed order-by-order in three dimensions.
We start by reviewing the a-function in even dimensions from a gradient-flow standpoint. Then we discuss our explicit calculations in three dimensions. Finally we present some progress towards relating our results to the F-function which has been shown to have the expected monotonicity properties at fixed points.
The a-theorem expressing the monotonicity of renormalisation group flows in four (and other even) dimensions is now well-accepted. There is a function (the a-function) generating the RG beta-functions as a gradient flow via a positive-definite metric. However the standard definition of the a-function in terms of the trace anomaly of the energy-momentum tensor does not work in odd dimensions. In this talk we focus on the gradient-flow property of the a-function and show that a function with similar properties can be constructed order-by-order in three dimensions.
We start by reviewing the a-function in even dimensions from a gradient-flow standpoint. Then we discuss our explicit calculations in three dimensions. Finally we present some progress towards relating our results to the F-function which has been shown to have the expected monotonicity properties at fixed points.
Posted by: IC