6.3k citations
Counting papers with at most 25 authors, so collaboration author lists do not stand in for the people here.
- Kyoto UniversityJP16 papers
- Tokyo Institute of TechnologyJP10 papers
- Inter-University Centre for Astronomy and AstrophysicsIN9 papers
- The University of TokyoJP9 papers
- Jamia Millia IslamiaIN8 papers
- Özyeğin UniversityTR8 papers
- Yukawa Institute for Theoretical PhysicsJP8 papers
- Advanced Science Research CenterJP7 papers
- Japan Atomic Energy AgencyJP7 papers
- Astronomical Observatory of RomeIT6 papers
- The University of OsakaJP5 papers
- Jožef Stefan InstituteSI4 papers
10 papers · 1 filter
Conditions for the cosmological viability of f(R) dark energy models
Luca Amendola, Radouane Gannouji, David Polarski +1
We derive the conditions under which dark energy models whose Lagrangian densities f are written in terms of the Ricci scalar R are cosmologically viable. We show that the cosmolog…
Realizing Scale-invariant Density Perturbations in Low-energy Effective String Theory
Zong-Kuan Guo, Nobuyoshi Ohta, Shinji Tsujikawa
We discuss the realization of inflation and resulting cosmological perturbations in the low-energy effective string theory. In order to obtain nearly scale-invariant spectra of den…
String-inspired cosmology: Late time transition from scaling matter era to dark energy universe caused by a Gauss-Bonnet coupling
Shinji Tsujikawa, M. Sami
The Gauss-Bonnet (GB) curvature invariant coupled to a scalar field can lead to an exit from a scaling matter-dominated epoch to a late-time accelerated expansion, which is att…
Avoidance of future singularities in loop quantum cosmology
M. Sami, Parampreet Singh, Shinji Tsujikawa
We consider the fate of future singularities in the effective dynamics of loop quantum cosmology. Non-perturbative quantum geometric effects which lead to modification of the…
Challenges for scaling cosmologies
Luca Amendola, Miguel Quartin, Shinji Tsujikawa +1
A cosmological model that aims at solving the coincidence problem should show that dark energy and dark matter follow the same scaling solution from some time onward. At the same t…
Power-laws f(R) theories are cosmologically unacceptable
Luca Amendola, David Polarski, Shinji Tsujikawa
In a recent paper [1] (PRL 98,131302,2007) we have shown that f(R)=R + mu R^{n} modified gravity dark energy models are not cosmologically viable because during the matter era that…
Dynamics of dark energy
Edmund J. Copeland, M. Sami, Shinji Tsujikawa
In this paper we review in detail a number of approaches that have been adopted to try and explain the remarkable observation of our accelerating Universe. In particular we discuss…
Are f(R) dark energy models cosmologically viable ?
Luca Amendola, David Polarski, Shinji Tsujikawa
All modified gravity theories are conformally identical to models of quintessence in which matter is coupled to dark energy with a strong coupling. This coupling induces a c…
General analytic formulae for attractor solutions of scalar-field dark energy models and their multi-field generalizations
Shinji Tsujikawa
We study general properties of attractors for scalar-field dark energy scenarios which possess cosmological scaling solutions. In all such models there exists a scalar-field domina…
Inflation from D3-brane motion in the background of D5-branes
Sudhakar Panda, M. Sami, Shinji Tsujikawa +1
We study inflation arising from the motion of a BPS D3-brane in the background of a stack of k parallel D5-branes. There are two scalar fields in this set up-- (i) the radion field…