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
9 papers · 1 filter
Constraints on Dirac-Born-Infeld type dark energy models from varying alpha
Mohammad R. Garousi, M. Sami, Shinji Tsujikawa
We study the variation of the effective fine structure constant alpha for Dirac-Born-Infeld (DBI) type dark energy models. The DBI action based on string theory naturally gives ris…
What is needed of a tachyon if it is to be the dark energy?
Edmund J. Copeland, Mohammad R. Garousi, M. Sami +1
We study a dark energy scenario in the presence of a tachyon field with potential and a barotropic perfect fluid. The cosmological dynamics crucially depends on the asym…
Chaotic dynamics in preheating after inflation
Yoshida Jin, Shinji Tsujikawa
We study chaotic dynamics in preheating after inflation in which an inflaton is coupled to another scalar field through an interaction . We first estimate t…
A unified approach to scaling solutions in a general cosmological background
Shinji Tsujikawa, M. Sami
Our ignorance about the source of cosmic acceleration has stimulated study of a wide range of models and modifications to gravity. Cosmological scaling solutions in any of these th…
Testing for double inflation with WMAP
David Parkinson, Shinji Tsujikawa, Bruce A. Bassett +1
With the WMAP data we can now begin to test realistic models of inflation involving multiple scalar fields. These naturally lead to correlated adiabatic and isocurvature (entropy)…
Observational constraints on patch inflation in noncommutative spacetime
Gianluca Calcagni, Shinji Tsujikawa
We study constraints on a number of patch inflationary models in noncommutative spacetime using a compilation of recent high-precision observational data. In particular, the four-d…
Observational constraints on braneworld inflation: the effect of a Gauss-Bonnet term
Shinji Tsujikawa, M. Sami, Roy Maartens
High-energy modifications to general relativity introduce changes to the perturbations generated during inflation, and the latest high-precision cosmological data can be used to pl…
Dilatonic ghost condensate as dark energy
Federico Piazza, Shinji Tsujikawa
We explore a dark energy model with a ghost scalar field in the context of the runaway dilaton scenario in low-energy effective string theory. We address the problem of vacuum stab…
Generation of electromagnetic fields in string cosmology with a massive scalar field on the anti D-brane
Mohammad R. Garousi, M. Sami, Shinji Tsujikawa
We study the generation of electromagnetic fields in a string-inspired scenario associated with a rolling massive scalar field on the anti-D3 branes of KKLT de Sitter vacua. Th…