Home Page of Raghavan Rangarajan

          Raghu's Photo Raghavan Rangarajan

Ph.D. University of California, Santa Barbara 1994
A.B. (cum laude) Princeton University 1988
Tel: +91 (79) 2631 4456
Fax: +91 (79) 2630 1502
e-mail: raghavan AT prl.res.in

Current Research Interests
My research has been in cosmology and particle physics, particularly on baryogenesis, inflation and the cosmic microwave background radiation. Baryogenesis is the mechanism of generating the matter-antimatter asymmetry observed in our Universe today. Over the last several years I have worked on different scenarios of baryogenesis involving black hole evaporation, heavy Majorana neutrinos, inflaton decay, out-of-equilibrium decays of heavy particles and the electroweak phase transition.

To explain certain cosmological problems, one invokes an era of accelerated expansion in the early universe, referred to as inflation. Density fluctuations generated during inflation can be the seed for structure formation and will leave an imprint on the cosmic microwave background radiation. My interests are in understanding the inflationary era and the subsequent reheating of the universe. I have worked on issues related to the fluctuations seen in the microwave background and on the generation of unwanted relics during reheating.

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.


Surveys in Theoretical High Energy Physics -2 -- Lecture Notes from SERC Schools
Ed: Raghavan Rangarajan and M. Sivakumar

Selected publications
  1. R. Arya, N. Mahajan and R. Rangarajan,
    Gravitino Production in a Thermal Universe Revisited
    Phys. Lett. B 772, 258 (2017).

  2. 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).

  3. R. Adhikari, A. Dasgupta, C. S. Fong and R. Rangarajan,
    Nonthermal CP Violation in Soft Leptogenesis,
    Phys. Rev. D 91, 096001 (2015).

  4. N. Mahajan, R. Rangarajan and A. Sarkar,
    Supersymmetric Flat Directions and Resonant Gravitino Production,
    Phys. Rev. D 90, 023522 (2014).

  5. R. Rangarajan and A. Sarkar,
    Kinetic and Chemical Equilibrium of the Universe and Gravitino Production,
    Astropart. Phys. 48, 37 (2013).

  6. M. Bastero-Gil, A. Berera, N. Mahajan and R. Rangarajan,
    Power Spectrum Generated during Inflation,
    Phys. Rev. D 87, 087302 (2013).

  7. A. Berera and R. Rangarajan,
    Quantum Phase of Inflation,
    Phys. Rev. D 87, 043514 (2013).

  8. 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).

  9. R. Rangarajan and N. Sahu,
    Perturbative Reheating and Gravitino Production in an Inflationary Models,
    Phys. Rev. D 79, 103534 (2009).

  10. 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).

  11. J. R. Bhatt and R. Rangarajan,
    Thermalisation in Thick Wall Electroweak Baryogenesis,
    Phys. Rev. D 75, 087305 (2007).

  12. K. Bhattacharya, S. Mohanty and R. Rangarajan,
    Temperature of the Inflaton and Duration of Inflation from WMAP Data,
    Phys. Rev. Lett. 96, 121302 (2006).

  13. J. R. Bhatt and R. Rangarajan,
    Studying Electroweak Baryogenesis using Evenisation and the Wigner Formalism,
    JHEP 03, 057 (2005).

  14. R. Adhikari and R. Rangarajan,
    Baryon Number Violation in Particle Decays,
    Phys.Rev.D 65, 083504 (2002).

  15. R. Rangarajan, S. Sengupta and A. Srivastava,
    Electroweak Baryogenesis in a Cold Universe,
    Astropart. Phys. 17, 167 (2002).

  16. R. Rangarajan and D. V. Nanopoulos,
    Inflationary Baryogenesis,
    Phys. Rev. D 64, 063511 (2001).

  17. R. Rangarajan and H. Mishra,
    Leptogenesis with Heavy Majorana Neutrinos Reexamined,
    Phys. Rev. D 61, 043509 (2000).

  1. 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].

  2. 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].

  3. 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.)

  4. 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).

Curriculum vitae

    Other Links

PRL                          SERCTHEP                         XXI SERC (THEP) School at PRL




Advanced B.Sc. (Physics) Programme

WHEPP XI - Cosmology and Astroparticle Physics Working Group (WG1)

Conferences, Workshops and Schools in Gravitation, Cosmology and Particle Physics in India

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