Strings : Monday, September 7, 2026, 2:00 PM, room 226
Andrea Campoleoni (Université de Mons, Belgian)
Hints for higher-spin holography in flat space
Higher-spin gauge theories in AdS have been conjectured to be dual to the large-N limit of the O(N) vector model. Although higher spins are often considered to be more problematic in flat space than in AdS, several ingredients of this duality admit a smooth flat limit. We focus on the symmetries underlying this correspondence. In particular, we discuss how higher-spin gauge theories in Minkowski space may be constructed by gauging a subalgebra of the symmetries of a Carrollian scalar defined at null infinity.
Strings : Tuesday, September 8, 2026, 2:00 PM, room 226
Stefan Fredenhagen (University of Vienna, Austria)
From flat space gravity to Carrollian W-algebras
I will discuss the relation between gravity in asymptotically flat spacetimes, Carrollian free fields, and extended W-symmetries. I will focus on how free-field and Miura-type constructions emerge from the gravitational description, and comment on their implications for Carrollian W_N-algebras and their quantization.
Strings : Tuesday, September 22, 2026, 2:00 PM, Adela Kochanovska Hall
Christopher M. Hull (Imperial College London, UK)
A New Superstring Field Theory
String field theory provides a 2nd quantised non-perturbative formulation of string theory. In this seminar, the field theory for the bosonic string is introduceded and the extension to the superstring discussed. Sen’s superstring field theory successfully formulates perturbative superstring theory but has a number of strange features. The action is not fully background independent and it does not have standard diffeomorphism symmetry - instead there is an exotic gauge symmetry that acts on some fields but not others. These issues greatly restrict the spacetimes that this action can be applied to. A new action is proposed that reduces to Sen’s in a certain limit, but which has diffeomorphism symmetry together with further exotic symmetries and is background independent. As a result, it can be applied to any spacetime.
Cosmo : Wednesday, September 23, 2026, 11:30 AM, lecture hall
Enrico Maraboli (Università degliStudi di Milano, Milan, Italy)
TBA
Strings : Thursday, September 24, 2026, 3:30 PM, Dvořák Lecture Hall
Poul H. Damgaard (Niels Bohr Institute, Denmark)
Solving perturbative gravitational dynamics by recursion.
Efficient tools from quantum field theory can with advatage be used to solve the Einstein field equations in pertubation theory. The formalism is recursive in nature, building each new order from combinations of terms already computed at lower orders.
Strings : Monday, October 12, 2026, 2:00 PM, room 226
Sitender Pratap Kashyap (FZU Prague, Czech Republic)
A field-inspired derivation of open string amplitudes
We propose a new method for computing N-point tree-level open string amplitudes, inspired by the field-theoretical perturbiner framework and bypassing world-sheet moduli integration. The construction rests on a weak associativity condition for a point-split, on-shell product of string vertices, introducing a binary-tree prescription with all physical channels manifest. The output is a multi-parametric series representation of the partial amplitude that is amenable to masslevel truncation and, therefore, numerical implementation. Besides the Veneziano amplitude, automatically represented by a dual-channel series with one free parameter, we present its five-point generalization, involving two free parameters and matched against known results in the literature. Higher multiplicities are obtained via the same systematic branching, with no separate input.