Triangle Seminars

Abstract:
Compact binaries with asymmetric mass ratios are key expected sources for next-generation gravitational-wave detectors. Gravitational self-force theory has been successful in producing post-adiabatic waveforms that describe the quasicircular inspiral around a nonspinning black hole with sub-radian accuracy, in remarkable agreement with numerical relativity simulations. Current self-force models, however, break down at the innermost stable circular orbit (ISCO), missing the final merger and ringdown stages. In this talk, I will show how the self-force waveforms can be extended beyond the ISCO, building first-principles inspiral-merger-ringdown waveforms. I will then dissect the final merger-ringdown waveforms and compare them with a self-consistently calculated sum over quasinormal modes and a stationary-phase approximation. Finally, I will briefly discuss how beyond-GR effects can be modularly added in this framework.

Abstract:
Symmetries of a quantum field theory are implemented by topological operators. These are special extended operators whose correlation functions are insensitive to continuous deformations of their support. The classification of generalized symmetries thus reduces to understanding the spectrum of such topological operators across different codimensions. While a generic QFT may admit infinitely many topological operators, their topological nature imposes strong consistency conditions on their structure. In this talk, I will present a set of such constraints in 2+1 and 3+1 dimensions and highlight how they severely restrict the spectrum of topological operators in higher dimensions, in contrast to 1+1 dimensions. Using these constraints, I will argue that the action of non-invertible symmetries on local operators in higher dimensions is highly restricted. In particular, this action is either invertible or, when non-invertible, admits a description in terms of gauging a finite symmetry.

Abstract:
TBC.