On scalar radiation
Abstract
We discuss radiation in theories with scalar fields. Our key observation is that even in flat spacetime, the radiative fields depend qualitatively on the coupling of the scalar field to the Ricci scalar: for non-minimally coupled scalars, the radiative energy density is not positive definite, the radiated power is not Lorentz invariant and it depends on the derivative of the acceleration. We explore implications of this observation for radiation in conformal field theories. First, we find a relation between two coefficients that characterize radiation, that holds in all the conformal field theories we consider. Furthermore, we find evidence that for a -BPS probe coupled to super Yang-Mills, and following an arbitrary trajectory, the spacetime dependence of the one-point function of the energy-momentum tensor is independent of the Yang-Mills coupling.
Cite
@article{arxiv.1907.08161,
title = {On scalar radiation},
author = {Bartomeu Fiol and Jairo Martínez-Montoya},
journal= {arXiv preprint arXiv:1907.08161},
year = {2020}
}
Comments
14 pages. v2: important typo fixed in equation (25). Minor edits. v3: Expanded version with a new section. A new computation has been added, showing that the full one-point function of the energy density in ${\cal N}=4$ SYM in the presence of a 1/2-BPS probe, displays the same spacetime dependence at weak and strong 't Hooft coupling. v4: tiny typo fixed