arXiv subjects

Noah Bittermann

Publications and source records attributed to Noah Bittermann.

4 recordsLinked to original sources

arXiv2022

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 an $RFF$ coupling in a de Sitter shockwave background as an illustrative example. We also briefly discuss connections to the ANEC.

hep-th↗

arXiv2022

Soft limits of the wavefunction in exceptional scalar theories

We study the structure of the flat space wavefunctional in scalar field theories with nonlinearly realized symmetries. These symmetries imply soft theorems that are satisfied by wavefunction coefficients in the limit where one of the external momenta is scaled to zero. After elucidating the structure of these soft theorems in the nonlinear sigma model, Dirac-Born-Infeld, and galileon scalar theories, we combine them with information about the singularity structure of the wavefunction to bootstrap the wavefunction coefficients of these theories. We further systematize this construction through two types of recursion relations: one that utilizes the flat space scattering amplitude plus minimal information about soft limits, and an alternative that does not require amplitude input, but does require subleading soft information.

hep-th↗

arXiv2020

${\cal N}=2$ Supersymmetric Partially Massless Fields and Non-Unitary Superconformal Representations

We find and classify the simplest ${\cal N}=2$ SUSY multiplets on AdS$_4$ which contain partially massless fields. We do this by studying representations of the ${\cal N}=2$, $d=3$ superconformal algebra of the boundary, including new shortening conditions that arise in the non-unitary regime. Unlike the ${\cal N}=1$ case, the simplest ${\cal N}=2$ multiplet containing a partially massless spin-2 is short, containing several exotic fields. More generally, we argue that ${\cal N}=2$ supersymmetry allows for short multiplets that contain partially massless spin-$s$ particles of depth $t=s-2$.

hep-th↗

arXiv2015

Modeling and Particle Tracking through Longitudinal Gradient Bending Magnets

This report documents the development of a versatile model for longitudinal gradient bending magnets (LGB's) and its implementation in particle tracking simulations. The model presented below may be used to represent an arbitrary magnetic field profile, and was successfully implemented to represent two different LGB's. After building a symplectic integrator for our model, we were able to perform particle tracking studies. By producing phase space plots which depicted stable trajectories, we were able to demonstrate that we had in fact correctly implemented our symplectic integration scheme. In addition, we produced stack representations for the bending component of the magnetic field for each LGB and made preliminary comparisons between lattices implementing this model and our own.

physics.acc-ph↗