Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - Towards a Resolution of the Cosmological Singularity in Non-local Higher Derivative Theories of Gravity
AU - Biswas, Tirthabir
AU - Koivisto, Tomi
AU - Mazumdar, Anupam
N1 - 38 pages, 6 figures. V2: Added: a word to the title, clarifications, an appendix, many references. To appear in JCAP
PY - 2010/11
Y1 - 2010/11
N2 - One of the greatest problems of standard cosmology is the Big Bang singularity. Previously it has been shown that non-local ghostfree higher-derivative modifications of Einstein gravity in the ultra-violet regime can admit non-singular bouncing solutions. In this paper we study in more details the dynamical properties of the equations of motion for these theories of gravity in presence of positive and negative cosmological constants and radiation. We find stable inflationary attractor solutions in the presence of a positive cosmological constant which renders inflation {\it geodesically complete}, while in the presence of a negative cosmological constant a cyclic universe emerges. We also provide an algorithm for tracking the super-Hubble perturbations during the bounce and show that the bouncing solutions are free from any perturbative instability.
AB - One of the greatest problems of standard cosmology is the Big Bang singularity. Previously it has been shown that non-local ghostfree higher-derivative modifications of Einstein gravity in the ultra-violet regime can admit non-singular bouncing solutions. In this paper we study in more details the dynamical properties of the equations of motion for these theories of gravity in presence of positive and negative cosmological constants and radiation. We find stable inflationary attractor solutions in the presence of a positive cosmological constant which renders inflation {\it geodesically complete}, while in the presence of a negative cosmological constant a cyclic universe emerges. We also provide an algorithm for tracking the super-Hubble perturbations during the bounce and show that the bouncing solutions are free from any perturbative instability.
KW - cosmic singularity
KW - modified gravity
KW - quantum gravity phenomenology
KW - alternatives to inflation
UR - http://www.scopus.com/inward/record.url?scp=78649844962&partnerID=8YFLogxK
U2 - 10.1088/1475-7516/2010/11/008
DO - 10.1088/1475-7516/2010/11/008
M3 - Journal article
VL - n/a
JO - Journal of Cosmology and Astroparticle Physics
JF - Journal of Cosmology and Astroparticle Physics
SN - 1475-7516
IS - 11
M1 - 008
ER -