Power-laws f(R) theories are cosmologically unacceptable

• Verfasst von: Amendola, Luca [VerfasserIn]
• Verfasst von: Polarski, David [VerfasserIn]
• Verfasst von: Tsujikawa, Shinji [VerfasserIn]
• Titel: Power-laws f(R) theories are cosmologically unacceptable
• Verf.angabe: Luca Amendola, INAF/Osservatorio Astronomico di Roma, Via Frascati 33, I-00040 Monte Porzio Catone, RM, Italy ; David Polarski, Lab. de Physique Mathématique et Théorique, Université Montpellier II, UMR 5825, 34095 Montpellier Cedex 05, France ; Shinji Tsujikawa, Department of Physics, Gunma National College of Technology, Gunma 371-8530, Japan
• Umfang: 7 S.
• Fussnoten: Gesehen am 15.11.2017
• Titel Quelle: Enthalten in: International journal of modern physics / D
• Jahr Quelle: 2007
• Band/Heft Quelle: 16(2007), 10, S. 1555-1561
• ISSN Quelle: 1793-6594
• DOI: doi:10.1142/S0218271807010936
• Datenträger: Online-Ressource
• Sprache: eng
• K10plus-PPN: 1565368851

Abstract

In a recent paper,1 we have shown that f(R) = R + μRn modified gravity dark energy models are not cosmologically viable because during the matter era that precedes the accelerated stage the cosmic expansion is given by a ~ t1/2 rather than a ~ t2/3, where a is a scale factor and t is the cosmic time. A recent work by Capozziello et al.2 criticized our results presenting some apparent counter-examples to our claim in f(R) = μRn models. We show here that those particular Rn models can produce an expansion as a ~ t2/3 but this does not connect to a late-time acceleration. Hence, though acceptable f(R) dark energy models might exist, the Rn models presented in Capozziello et al. are not cosmologically viable, confirming our previous results in Ref. 1.