Faculty Fellows

Professor Raghavan Rangarajan is Dean and Professor at the School of Arts and Sciences, Ahmedabad University.

He was on the faculty of the Theoretical Physics Division at the Physical Research Laboratory (PRL), Ahmedabad for over twenty years before joining Ahmedabad University. His areas of research are cosmology and particle physics, and he works primarily on processes that occurred soon after the Big Bang in the very early Universe. In particular, his research has been on topics such as dark matter, the matter-antimatter asymmetry of the universe and cosmic microwave background radiation. He obtained his PhD from the University of California, Santa Barbara in 1994, and his undergraduate degree from Princeton University in 1988.

Professor Rangarajan has been actively involved in programmes that bring together college students and academic researchers. He is an editor of the journal ‘Physics Education’ of the Indian Association of Physics Teachers.

Education Details
Ph.D., Physics, 1994, University of California, Santa Barbara
A.B., Physics (cum laude), 1988, Princeton University, New Jersey

Employment Details

• Dean of School of Arts and Sciences, Ahmedabad University, Ahmedabad, July 2022 – Present
• Dean of the Undergraduate College, Ahmedabad University, Ahmedabad, January 2018 – July 2022
• Dean of Students, Ahmedabad University, Ahmedabad, June 2018 - January 2020
• Professor, Division of Mathematical and Physical Sciences, School of Arts and Sciences, Ahmedabad University, Ahmedabad, January 2018 - Present
• Professor, Associate Professor, Reader, Scientist D, Theoretical Physics Division, Physical Research Laboratory, Ahmedabad, November 1997 – January 2018
• Post-Doctoral Fellow, Astroparticle Physics Group, Houston Advanced Research Center, Texas, September 1995 - September 1997
• Post-Doctoral Fellow, High Energy Theory Group, Physics Dept., University of California, Santa Barbara, September 1994 - June 1995
• Lecturer, Physics Dept., University of California, Santa Barbara, June 1994 - July 1994, January 1995 - June 1995

Courses Taught
At Physical Reasearch Laboratory

• General Relativity and Cosmology
• Advanced Quantum Mechanics
• Advanced Quantum Mechanics and Quantum Field Theory
• Quantum Field Theory
• Quantum Mechanics
• Electrodynamics
• Mathematical Methods in Physics

OTHER COURSES

• Modern Physics (IIT Gandhinagar, 2010-11)
• Cosmology (short course at IIT Gandhinagar, 2010)
• Thermal Field Theory (XXIII SERC Main School in Theoretical High Energy Physics, IIT Bombay, 2008)
• Physics for Physics/Engineering students (2 courses at University of California, Santa Barbara, 1995)
• Physics for Biology students (University of California, Santa Barbara, 1994)
• Physics Laboratory (Asst. Laboratory Instructor at Princeton University, 1988)

SUMMARY OF RESEARCH
My research interests are in cosmology and particle physics, particularly in inflation (a period of accelerated expansion in the early Universe), and in high energy phenomena that occur in an inflationary Universe. I have been interested in the dynamics of inflation, in the generation of energy density perturbations during inflation, in the production of unwanted particles in the early Universe after inflation, etc. In addition, I have also been interested in understanding mechanisms to explain the observed matter-antimatter asymmetry of the Universe, or baryogenesis. In the past I have worked on different scenarios of baryogenesis involving black hole evaporation, heavy Majorana neutrinos, inflation decay, out-of-equilibrium decays of heavy particles and baryogenesis during the electroweak phase transition.
BOOKS

1. Surveys in Theoretical High Energy Physics 2: Lecture Notes from SERC Schools, Texts and Readings in Physical Sciences - 15, edited by Raghavan Rangarajan and M. Sivakumar, Hindustan Book Agency, 2014.
2. Cosmology - The Story of our Universe in Scientific Perspectives of Jainism, edited by Samani Chaitanya Prajna, N. Bhandari and N. L. Kachhara, Jain Vishva Bharati Institute, Ladnun, Rajasthan, 2017.
3. Cosmic Microwave Background Radiation and Inflation in Modern Atomism (History of Science, Philosophy and Culture in Indian Civilization, Vol XII, Part 4), edited by J. Pasupathy, Centre for Studies in Civilizations, Munshiram Manoharlal Publishers, 2017.

SELECTED PUBLICATIONS

1. R. Arya, A. Dasgupta, G. Goswami, J. Prasad and R. Rangarajan,Revisiting CMB Constraints on Warm Inflation,JCAP 1802, 043 (2018).
2. R. Arya, N. Mahajan and R. Rangarajan,Gravitino Production in a Thermal Universe Revisited,Phys. Lett. B 772, 258 (2017).
3. S. Das, G. Goswami, R. Rangarajan and Jayanti Prasad, Constraints on Just Enough Inflation Preceded by a Thermal Era,Phys. Rev. D 93, 023516 (2016).
4. R. Adhikari, A. Dasgupta, C. S. Fong and R. Rangarajan,Nonthermal CP Violation in Soft Leptogenesis,Phys. Rev. D 91, 096001 (2015).
5. N. Mahajan, R. Rangarajan and A. Sarkar,Supersymmetric Flat Directions and Resonant Gravitino Production,Phys. Rev. D 90, 023522 (2014).
6. R. Rangarajan and A. Sarkar,Kinetic and Chemical Equilibrium of the Universe and Gravitino Production,Astropart. Phys. 48, 37 (2013).
7. M. Bastero-Gil, A. Berera, N. Mahajan and R. Rangarajan,Power Spectrum Generated during Inflation,Phys. Rev. D 87, 087302 (2013).
8. A. Berera and R. Rangarajan,Quantum Phase of Inflation,Phys. Rev. D 87, 043514 (2013).
9. N. Mahajan and R. Rangarajan,Remarks on Non-gaussian Fluctuations of the Inflaton and Constancy of zeta Outside the Horizon,Phys. Rev. D 83, 043510 (2011).
10. R. Rangarajan and N. Sahu,Perturbative Reheating and Gravitino Production in an Inflationary Models,Phys. Rev. D 79, 103534 (2009).
11. A. Shafieloo, T. Souradeep, P. Manimaran, P. K. Panigrahi and R. Rangarajan,Features in the Primordial Spectrum from WMAP: A Wavelet Analysis,Phys. Rev. D 75, 123502 (2007).
12. J. R. Bhatt and R. Rangarajan,Thermalisation in Thick Wall Electroweak Baryogenesis,Phys. Rev. D 75, 087305 (2007).
13. K. Bhattacharya, S. Mohanty and R. Rangarajan,Temperature of the Inflaton and Duration of Inflation from WMAP Data,Phys. Rev. Lett. 96, 121302 (2006).
14. J. R. Bhatt and R. Rangarajan,Studying Electroweak Baryogenesis using Evenisation and the Wigner Formalism,JHEP 03, 057 (2005).
15. R. Adhikari and R. Rangarajan,Baryon Number Violation in Particle Decays,Phys. Rev.D 65, 083504 (2002).
16. R. Rangarajan, S. Sengupta and A. Srivastava,Electroweak Baryogenesis in a Cold Universe,Astropart. Phys. 17, 167 (2002).
17. R. Rangarajan and D. V. Nanopoulos,Inflationary Baryogenesis,Phys. Rev. D 64, 063511 (2001).
18. R. Rangarajan and H. Mishra,Leptogenesis with Heavy Majorana Neutrinos Reexamined,Phys. Rev. D 61, 043509 (2000).

Reviews

1. R. Rangarajan,
   Current Status of Warm Inflation,
   Slightly longer version of a brief review talk at the 18th Lomonosov Conference on Elementary Particle Physics at Moscow State University, August 24-30, 2017,
   arXiv:1801.02648 [astro-ph.CO]
2. R. Rangarajan,
   Inflation after Planck and BICEP2,
   Slightly longer version of a plenary review talk at the XXI DAE-BRNS High Energy Physics Symposium at IIT Guwahati, 8-12 Dec 2014,
   arXiv:1506.07433 [astro-ph.CO].
3. R. Rangarajan,
   WMAPping the inflationary universe,
   17th DAE-BRNS High Energy Physics Symposium at the Indian Institute of Technology, Kharagpur, 11-15 Dec 2006,
   arXiv:0706.4166 [hep-ph].
4. S. Goswami and R. Rangarajan,
   Working group report: Neutrino and astroparticle physics,
   8th Workshop on High-Energy Physics Phenomenology (WHEPP 8), Bombay, India, 5-16 Jan 2004,
   Pramana 63, 1391-1406 (2004), [hep-ph/0409225]. (This contains a useful introduction to CMBFAST.)
5. R. Rangarajan,
   Baryogenesis in the early universe,
   Prepared for the Workshop on Cosmology: Observations Confront Theories, Kharagpur, India, 4-11 Jan 1999,
   Pramana 53, 1061-1067 (1999).

Some Public Talks

1. Lectures on Cosmology: Lecture 1 | Lecture 2  | Lecture 3| Lecture 4
2. Cosmology - The Story of our Universe
3. Elementary Particles in Nature and the Search for the Higgs Boson
4. General Relativity and Gravitation
5. SynTalk on The Large and Small (a discussion involving a mathematician, a biologist and a cosmologist)
6. My TEDx talk on Chasing the Elusive Dark Matter and the slides of the talk.
7. Black Holes in Stephen Hawking's Universe
8. Ask How About: Cosmology Part 1 | Part 2

OTHER ACTIVITIES

• 2014 – Present, National Coordinator, Physics Training and Talent Search (PTTS)
• 2011 – Present, Member, Board of Editors, Physics Education (a journal of the Indian Association of Physics Teachers - IAPT)
• 2003 – 2017, Coordinator, Advanced B.Sc. (Physics) Programme

National Directory of Conferences, Workshops and Schools in Gravitation, Cosmology and Particle Physics