Observational Evidence for Negative-Energy Dust in Late-Times Cosmology
| dc.creator | Mavromatos, Nikolaos E. | |
| dc.creator | Mitsou, Vasiliki A. | |
| dc.date | 2007-07-31 | |
| dc.date.accessioned | 2026-07-07T11:41:39Z | |
| dc.date.available | 2026-07-07T11:41:39Z | |
| dc.description | We perform fits of unconventional dark energy models to the available data from high-redshift supernovae, distant galaxies and baryon oscillations. The models are based either on brane cosmologies or on Liouville strings in which a relaxation dark energy is provided by a rolling dilaton field (Q-cosmology). An interesting feature of such cosmologies is the possibility of effective four-dimensional negative-energy dust and/or exotic scaling of dark matter. An important constraint that can discriminate among models is the evolution of the Hubble parameter as a function of the redshift, H(z). We perform fits using a unifying formula for the evolution of H(z), applicable to different models. We find evidence for a negative-energy dust at the current era, as well as for exotic-scaling (a^{-delta}) contributions to the energy density, with 3.3<delta<4.3. The latter could be due to dark matter coupling with the dilaton in Q-cosmology models, but it is also compatible with the possibility of dark radiation from a brane Universe to the bulk in brane-world scenarios, which could also encompass Q-cosmology models. The best-fit model seems to include an a^{-2}-scaling contribution to the energy density of the Universe, which is characteristic of the dilaton relaxation in Q-cosmology models, not to be confused with the spatial curvature contribution of conventional cosmology. We conclude that Q-cosmology fits the data equally well with the Lambda-CDM model for a range of parameters that are in general expected from theoretical considerations. | |
| dc.description | 21 pages LaTeX, 8 EPS figures incorporated | |
| dc.identifier | https://arxiv.org/abs/0707.4671 | |
| dc.identifier | http://arxiv.org/abs/0707.4671 | |
| dc.identifier | Astropart.Phys.29:442-452,2008 | |
| dc.identifier | doi:10.1016/j.astropartphys.2008.05.002 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/200613 | |
| dc.subject | Astrophysics | |
| dc.subject | General Relativity and Quantum Cosmology | |
| dc.subject | High Energy Physics - Theory | |
| dc.title | Observational Evidence for Negative-Energy Dust in Late-Times Cosmology | |
| dc.type | text |