Preprints 2022

Authors: Franziska Porkert, Oliver Schlotterer

Preprint number: UUITP-04/22

We present a method to compute the integrands of one-loop Einstein-Yang-Mills amplitudes for any number of external gauge and gravity multiplets. Our construction relies on the double-copy structure of Einstein-Yang-Mills as (super-)Yang-Mills with the so-called YM+phi^3 theory -- pure Yang-Mills coupled to bi-adjoint scalars -- which we implement via one-loop Cachazo-He-Yuan formulae. The YM+phi^3 building blocks are obtained from forward limits of tree-level input in external gluons and scalars, and we give the composition rules for any number of traces and orders in the couplings g and kappa. One the one hand, we spell out supersymmetry- and dimension-agnostic relations that reduce loop integrands of Einstein-Yang-Mills to those of pure gauge theories. On the other hand, we present four-point results for maximal and half-maximal supersymmetry where all supersymmetry cancellations are exposed. In the half-maximal case, we determine six-dimensional anomalies due to chiral hypermultiplets in the loop.

Authors: Ulf Danielsson, Daniel Panizo and Rob Tielemans

Preprint number: UUITP-03/22

Abstract: In this paper we construct the 5D uplift of 4D gravitational waves in de Sitter cosmology for the brane world scenario based on a nucleated bubble in AdS5. This makes it possible to generalize the connection between the dark bubbles and Vilenkin's quantum cosmology to include gravitational perturbations. We also use the uplift to explain the interpretation of the apparently negative energy contributions in the 4D Einstein equations, which distinguish the dark bubble scenario from Randall-Sundrum.

Authors: L. B. Anderson, J. Gray, M. Larfors, M. Magill

Preprint number: UUITP-02/22

Abstract: We provide an overview of recent work which aims to understand patterns of vanishing Yukawa couplings that arise in models of particle physics derived from string theory. These patterns are seemingly linked to a plethora of different geometrical structures and our understanding of the subject has yet to be consolidated in a unified framework. This short note is based upon a talk that was given by one of the authors at the Nankai Symposium on Mathematical Dialogues. Therefore it is aimed at a mathematical audience of mixed academic background.

Authors: Michele Del Zotto, Jonathan J. Heckman, Shani Nadir Meynet, Robert Moscrop, Hao Y. Zhang

Preprint number: UUITP-01/22

Abstract: We determine the higher symmetries of 5d SCFTs engineered from M-theory on a C³/Γ background for Γ a finite subgroup of SU(3). This resolves a longstanding question as to how to extract this data when the resulting singularity is non-toric (when Γ is non-abelian) and/or not isolated (when the action of Γ has fixed loci). The BPS states of the theory are encoded in a 1D quiver quantum mechanics gauge theory which determines the possible 1-form and 2-form symmetries. We also show that this same data can also be extracted by a direct computation of the corresponding defect group associated with the orbifold singularity. Both methods agree, and these computations do not rely on the existence of a resolution of the singularity. We also observe that when the geometry faithfully captures the global 0-form symmetry, the abelianization of Γ detects a 2-group structure (when present). As such, this establishes that all of this data is indeed intrinsic to the superconformal fixed point rather than being an emergent property of an IR gauge theory phase.