Triangle Seminars

Abstract:
There exist, in d=2+1 dimensions, field theories that are supersymmetric but non-relativistic. I will show that the low-energy physics of these theories is that of the fractional quantum Hall effect. Supersymmetry provides enough analytic control to explicitly derive the ground state wavefunctions and their excitations.

Abstract:
We would like to talk about all kinds of supersymmetric and non-supersymmetric scattering amplitudes of type IIA,IIB superstring theory as well as their corrections.

In fact we want to address how to get to a universal conjecture for DBI, Chern-Simons and more importantly new Wess Zumino actions with their all order \(\alpha'\) corrections. Indeed we try to provide a comprehensive explanation even for D- brane-anti D-brane systems, where various new techniques will be also introduced. If time allows , we then mention several issues related to those effective actions and eventually highlight some comments about higher point functions of the Mixed closed string RR , scalar fields in different pictures of the string theory amplitude.

Abstract:
The talk reports on recent progress in amplitude computations
for broad classes of N=2 Maxwell-Einstein and Yang-Mills-Einstein
supergravities, using the framework provided by color/kinematics duality
and the double-copy construction.
After a review of the main theoretical tools employed in the
computations, we discuss the extension of the double-copy construction
to a particular infinite family of N=2 Maxwell-Einstein supergravities
in four and five dimensions and show that the global symmetries of these
theories can easily be gauged, giving the amplitudes of the
corresponding Yang-Mills-Einstein supergravities. Finally, we discuss
how the construction can be modified to describe spontaneous symmetry
breaking and present examples at one loop.

Abstract:
The aim of this talk is to extract the quadratic corrections to Fronsdal equations from Vasiliev's equations, and discuss their structure. The issue of locality in higher-spin theories will be addressed. Implications of this analysis in relation to Giombi-Yin checks of higher-spin/vector model duality will be discussed. Some of the previous puzzles will be resolved, while others will be elucidated.

Abstract:
Remarkable formulae for the tree-level S-matrix of gauge and gravity
theories were recently discovered by Cachazo-He-Yuan, based on a
localisation procedure in the moduli space of Riemann surfaces.
These formulae are now known to arise from new string-like chiral
models. These naturally produces loop-level amplitudes, also localised
in the moduli space of higher genus curves.
However, the resolution of the localisation equations is immensely
more difficult than at tree-level, and it remained as an open question
as to what these formulae computed, and more generally if these string
models made sense at the quantum level.
In this talk I'll describe a resolution of the localisation equations
at one-loop in a particular kinematical regime, and show agreement
with known amplitudes.
Then I'll describe a much more powerful method, based on an
integration by parts which degenerates the torus down to a sphere
(plus two new points). The model is then solved like at
tree-level. I'll briefly discuss extension to higher loops in conclusion.