We consider cosmological solutions to general relativity with a single barotropic fluid, where the pressure is a general function of the density, p = f(ρ). We derive conditions for static and oscillating solutions and provide examples, extending earlier work to these simpler and more general single-fluid cosmologies. Generically we expect such solutions to suffer from instabilities, through effects such as quantum fluctuations or tunneling to zero size. We also find a classical instability (``no-go'' theorem) for oscillating solutions of a single barotropic perfect fluid due to a necessarily negative squared sound speed.
Journal of Cosmology and Astroparticle Physics
- Pub Date:
- December 2015
- High Energy Physics - Theory;
- Astrophysics - Cosmology and Nongalactic Astrophysics;
- General Relativity and Quantum Cosmology
- 5 pages