Raghavan Rangarajan is associate professor at the Theoretical Physics Division at the Physical Research Laboratory (PRL), Ahmedabad, since 1997. Prior to joining to PRL, he was a student at Princeton University and the University of California at Santa Barbara, and a postdoctoral fellow at the Houston Advanced Research Centre. His areas of research are cosmology and particle physics. He has worked on different subjects in these fields such as dark matter, the matter anti-matter asymmetry of the universe, and the cosmic microwave background radiation. M. Sivakumar is professor at the School of Physics, University of Hyderabad, India. His areas of interest are field theory, elementary particle physics, theoretical physics, and electromagnetism. He is a Fellow of the Andhra Pradesh Academy of Sciences and the Telangana Academy of Sciences. He was associate member of Abdus Salam International Center for Theoretical Physics, Trieste, Italy.