Welcome to Tsujikawa Laboratory
                      (Cosmology group)

 Last updated 26/October/ 2019

Shinji Tsujikawa's Lab. Members: Click here
Department of Physics,
Faculty of Science,
Tokyo University of Science,
1-3 Kagurazaka, Shinjuku-ku,
Tokyo, 162-8601, Japan

(Building  No. 1, 8-th floor)

+81-3-5228-8150  (ext.) 2391
Fax: +81-3-5261-1023

Click here for the access of our group
(Kagurazaka Campus)



Profile of Shinji Tsujikawa : 
Click here. You can also go to the personal webpage.

Research field : Cosmology, Relativity

List of papers in Tsujikawa's Lab: Click here.

Networks of collaborations: 
Click here.

Visitors: Click here.

Research activities: We have entered a golden age where cosmology can be probed
by high-presicion observational data.
It is of interest to investigate

       (1) The origin of elementary particles, dark energy and dark matter
       (2) The origin and evolution of cosmological density perturbations
            responsible for CMB and large scale structure.
Construction of cosmological models such as inflation based on
            particle physics (string theory, quantum gravity etc).

Our main research interest is to reveal the physical phenomena in the
early and late universes by confronting theoretical predictions with
observational data.
We would like to construct viable cosmological models that are most
favoured from observations.
In particular we are working on the research topics listed below:

Inflationary Universe
Particle creations in early universe
String cosmology
Physics of Cosmic Microwave Background (CMB)
Evolution of cosmological perturbations and large scale structure
Dark energy
Loop quantum gravity
Modified gravity and observational & experimental constraints
Black holes
Neutrino Physics

In particular we place observational constraints on the physics in
early universe (such as inflation) using recent observational data
of CMB (see figure 1).
We also try to understand the origin of dark energy that consists
of 70% of the energy density of the present Universe
(see figure 2).

[Figure 1] Temparature anisotroies in CMB (WMAP, 2006).
              The black points represent observational data and 
              the red curve corresponds to theoretical predictions.
              Inflationary cosmology predicts almost scale-invariant
              spectra of density perturbations, which matches very
              well with observational data of CMB anisotropies.

[Figure2]  The components in the present Universe.
              Dark Energy (74%) is an unknown energy which leads to
              an accelerated expansion of the universe.
Dark Matter (22%) is also an unknow matter which is
              pressureless (this does not leads to accelerated expansion).
         We only know the rest of the components in the Universe
              (Atoms, 4%).

       Inflation dynamics and reheating
       Reviews of Modern Physics 78, 537-589 (2006)
         Bruce A. Bassett (Capetown, South Africa),  David Wands (Portsmouth, UK)
         and Shinji Tsujikawa
   You can download this paper from astro-ph/0507632

       Dynamics of dark energy
      International Journal of Modern Physics D15, 1753-1936 (2006),
Edmund J. Copeland (Nottingham, UK), M. Sami (Jamia Millia Islamia, India)
          and Shinji Tsujikawa
You can download this paper from hep-th/0603057.