Absence of gyratons in the Robinson-Trautman class

Article

Absence of gyratons in the Robinson-Trautman class

Švarc, R.; Podolský, J.

Phys. Rev. D 89(12), 124029 (2014)

Abstract

We present the Riemann and Ricci tensors for a fully general non-twisting and shear-free geometry in arbitrary dimension D. This includes both the non-expanding Kundt and expanding Robinson-Trautman family of spacetimes. As an interesting application of these explicit expressions we then integrate the Einstein equations and prove a surprising fact that in any D the Robinson-Trautman class does not admit solutions representing gyratonic sources, i.e., matter field in the form of a null fluid (or particles propagating with the speed of light) with an additional internal spin. Contrary to the closely related Kundt class and pp-waves, the corresponding off-diagonal metric components thus do not encode the angular momentum of some gyraton. Instead, we demonstrate that in standard D=4 general relativity they directly determine two independent amplitudes of the Robinson-Trautman exact gravitational waves.

Keywords

gyratons, Robinson–Trautman class, Kundt class, gr avitational waves

Institute authors

Supported by

GACR 203/12/0118 — Spacetimes and Fields in Higher Dimensional and Classical Gravity

BibTeX

@article{UTF506,
  author        = {Švarc, R. and Podolský, J.},
  title         = {{Absence of gyratons in the Robinson-Trautman class}},
  journal       = {Phys. Rev. D},
  volume        = {89},
  number        = {12},
  pages         = {124029},
  year          = {2014},
  month         = {6},
  doi           = {http://dx.doi.org/10.1103/PhysRevD.89.124029},
  eprint        = {1406.0729},
  archivePrefix = {arXiv},
}