Will the tachyonic universe survive the big brake?

We investigate a Friedmann universe filled with a tachyon scalar field, which behaved as dustlike matter in the past, while it is able to accelerate the expansion rate of the Universe at late times. The comparison with type Ia supernovae (SNIa) data allows for evolutions driving the Universe into a...

Teljes leírás

Elmentve itt :
Bibliográfiai részletek
Szerzők: Keresztes Zoltán
Gergely Árpád László
Kamenshchik Alexander Yu
Gorini Vittorio
Polarski David
Dokumentumtípus: Cikk
Megjelent: American Physical Society 2010
Sorozat:PHYSICAL REVIEW D 82
doi:10.1103/PhysRevD.82.123534

mtmt:1604485
Online Access:http://publicatio.bibl.u-szeged.hu/7961
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520 3 |a We investigate a Friedmann universe filled with a tachyon scalar field, which behaved as dustlike matter in the past, while it is able to accelerate the expansion rate of the Universe at late times. The comparison with type Ia supernovae (SNIa) data allows for evolutions driving the Universe into a Big Brake. Some of the evolutions leading to a Big Brake exhibit a large variation of the equation of state parameter at low redshifts, which is potentially observable with future data, though hardly detectable with present SNIa data. The soft Big Brake singularity occurs at finite values of the scale factor, vanishing energy density and Hubble parameter, but diverging deceleration and infinite pressure. We show that the geodesics can be continued through the Big Brake and that our model universe will recollapse eventually in a Big Crunch. Although the time to the Big Brake strongly depends on the present values of the tachyonic field and of its time derivative, the time from the Big Brake to the Big Crunch represents a kind of invariant time scale for all field parameters allowed by SNIa. © 2010 The American Physical Society. 
700 0 1 |a Gergely Árpád László  |e aut 
700 0 1 |a Kamenshchik Alexander Yu  |e aut 
700 0 1 |a Gorini Vittorio  |e aut 
700 0 1 |a Polarski David  |e aut 
856 4 0 |u http://publicatio.bibl.u-szeged.hu/7961/1/49_cikk_keresztesetal2010.pdf  |z Dokumentum-elérés  
856 4 0 |u http://publicatio.bibl.u-szeged.hu/7961/2/49_cikk_preprint_1009.0776v2.pdf  |z Dokumentum-elérés