Relativistic rigid systems and the cosmic expansion
General Relativity and Quantum Cosmology
2020-08-28 v1
Abstract
We analyze the necessary conditions for a body to remain rigid in an expanding cosmological Universe. First, we establish the main theorems and definitions for having a rigid body in a general spacetime as well as the new concept of quasilocal rigidity. We apply the obtained results to a homogeneous universe exploring the differences with flat spacetime. We discuss how the concept of rigid body helps to understand the expansion of space in cosmology. Finally, using a rigid system as a reference frame, we calculate the gravitational energy, and we compare it with previous results in the literature.
Keywords
Cite
@article{arxiv.2008.11836,
title = {Relativistic rigid systems and the cosmic expansion},
author = {Luciano Combi and Gustavo E. Romero},
journal= {arXiv preprint arXiv:2008.11836},
year = {2020}
}
Comments
Accepted for publication in General Relativity and Gravitation. 20 pages, 2 figures