Bharat Ratra
Professor
Address:	32A Cardwell Hall
Phone:	(785) 532-6265
E-mail:	ratra@phys.ksu.edu
Personal Webpage
Ph.D. Stanford University, 1986
M.S. Indian Institute of Technology, New Delhi, 1982

Research Area

Cosmology and Astroparticle Physics

My current research focuses on developing and testing cosmological models for the large-scale matter and radiation distributions in the universe.

A primary goal is to test Einstein's general relativity on extremely large spatial- and temporal-scales, inaccessible to any other method. More immediate goals include determining the geometry and contents of the universe and how large-scale structure in the universe was formed. The cosmological models studied include currently popular ones that are spatially flat and dominated by dark energy (developed in collaboration with Jim Peebles). Of particular interest are the predictions these models make for the cosmic microwave background radiation (CMBR) anisotropy.

Other interests include inflation, dark matter, the classical cosmological tests, cosmological simulations of low- and intermediate-redshift large-scale structure, and cosmological magnetic fields.

We collaborate with the Kansas State University High Energy Physics Group.

Recent Support

• Department of Energy
• Kansas State University Targeted Excellence

Recent Selected Publications

• "Supernova Ia and Galaxy Cluster Gas Mass Fraction Constraints on Dark Energy," K.M. Wilson, G. Chen and B. Ratra, Mod. Phys. Lett. A 21, 2197 (2006).
• "Cosmological Constraints from Hubble Parameter versus Red­shift Data,"  L. Samushia and B. Ratra,  Astrophys. J. Lett. 650, L5 (2006).
• "Inflation and accelerated expansion teves cosmological solutions," Luz Maria Diaz-Rivera, Lado Samushia and Bharat Ratra , Phys Rev. D 73, 083503 (2006).
• "Polarized cosmological gravitational waves from primordial helical turbulence," Tina Kahniashvili, Grigol Gogoberidze, Bharat Ratra, Phys. Rev. Lett. 95, 151301 (2005).
• "Effects of cosmological magnetic helicity on the cosmic microwave background," Tina Kahniashvili and Bharat Ratra, Phys. Rev. D 71, 103006 (2005).
• Neutrino mass limit from galaxy cluster number density evolution, Tina Kahniashvili, Eckhard von Toerne, Natalia A. Arhipova and Bharat Ratra, Phys. Rev. D 71, 125009 (2005).
• "Faraday rotation of the Cosmic Microwave Background polarization by a stochastic magnetic field," Arthur Kosowsky, Tina Kahniashvili, George Lavrelashvili and Bharat Ratra, Phys. Rev. D 71, 043006 (2005).