Engineering topics

Bittermann, Noah

Publications and source records attributed to Bittermann, Noah.

2 records

DOE OSTI2023

On causality conditions in de Sitter spacetime

We carefully consider the Shapiro time delay due to black holes and shockwaves in de Sitter spacetime and study the implications for causality. We discuss how causality conditions of AdS and flat spacetime can be applied in de Sitter spacetime, using spatial shifts measured on the boundary to define 'fastest null geodesics' and taking into account the 'stretching' of the de Sitter Penrose diagram. We consider the propagation of a massless spin-1 field with a non-minimal coupling in a de Sitter shockwave background as an illustrative example. Here, we also briefly discuss connections to the average null energy condition.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2021

\( \mathcal{N} \) = 2 supersymmetric partially massless fields and other exotic non-unitary superconformal representations

We find and classify the simplest \( \mathcal{N} \) = 2 SUSY multiplets on AdS 4 which contain partially massless fields. We do this by studying representations of the \( \mathcal{N} \) = 2, d = 3 superconformal algebra of the boundary, including new shortening conditions that arise in the non-unitary regime. Unlike the \( \mathcal{N} \) = 1 case, the simplest \( \mathcal{N} \) = 2 multiplet containing a partially massless spin-2 is short, containing several exotic fields. More generally, we argue that \( \mathcal{N} \) = 2 supersymmetry allows for short multiplets that contain partially massless spin- s particles of depth t = s – 2.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗