Publications

Listed below are my publications in reverse chronological order. You can also find them listed at the INSPIRE, arXiv and Google Scholar sites.

Preprints

  1. S. Tripathy, D. Chowdhury, H. V. Ragavendra and L. Sriramkumar, Cross-correlation between the curvature perturbations and magnetic fields in pure ultra slow roll inflation, arXiv:2409.20232 [astro-ph.CO].
  2. S. Maity, N. Bhaumik, Md. R. Haque, D. Maity and L. Sriramkumar, Constraining the history of reheating with the NANOGrav 15-year data, arXiv:2403.16963 [astro-ph.CO].
  3. S. Maiti, D. Maity and L. Sriramkumar, Constraining inflationary magnetogenesis and reheating via GWs in light of PTA data, arXiv:2401.01864 [astro-ph.CO].

Publications in refereed journals

As articles and letters

  1. S. Barman, B. R. Majhi and L. Sriramkumar, Radiative processes of single and entangled detectors on circular trajectories in (2 + 1)-dimensional Minkowski spacetime, Phys. Rev. D. 109, 105025 (2024) [arXiv:2205.01305 [gr-qc]].
  2. S. Maity, H. V. Ragavendra, S. K. Sethi and L. Sriramkumar, Loop contributions to the scalar power spectrum due to quartic order action in ultra slow roll inflation, JCAP 05, 046 (2024) [arXiv:2307.13636 [astro-ph.CO]].
  3. W. H. Kinney, S. Maity and L. Sriramkumar, Borde-Guth-Vilenkin theorem in extended de Sitter spaces, Phys. Rev. D 109, 043519 (2024) [arXiv:2307.10958 [gr-qc]].
  4. S. Tripathy, R. N. Raveendran, K. Parattu and L. Sriramkumar, Amplifying quantum discord during inflationary magnetogenesis through violation of parity, Phys. Rev. D 108, 123512 (2023) [arXiv:2306.16168 [gr-qc]].
  5. S. Tripathy, D. Chowdhury, H. V. Ragavendra, R. K. Jain and L. Sriramkumar, Circumventing the challenges in the choice of the non-conformal coupling function in inflationary magnetogenesis, Phys. Rev. D 107, 043501 (2023) [arXiv:2211.05834 [astro-ph.CO]].
  6. S. Balaji, H. V. Ragavendra, S. K. Sethi, J. Silk and L. Sriramkumar, Observing nulling of primordial correlations via the 21 cm signal, Phys. Rev. Lett. 129, 261301 (2022) [arXiv:2206.06386 [astro-ph.CO]].
  7. R. N. Raveendran, K. Parattu and L. Sriramkumar, Enhanced power on small scales and evolution of quantum state of perturbations in single and two field inflationary models, Gen. Rel. Grav. 54, 91 (2022) [arXiv:2206.05760 [astro-ph.CO]].
  8. H. V. Ragavendra, D. Chowdhury and L. Sriramkumar, Suppression of scalar power on large scales and associated bispectra, Phys. Rev. D 106, 043535 (2022) [arXiv:2003.01099 [astro-ph.CO]].
  9. S. Tripathy, D. Chowdhury, R. K. Jain and L. Sriramkumar, Challenges in the choice of the nonconformal coupling function in inflationary magnetogenesis, Phys. Rev. D 105, 063519 (2022) [arXiv:2111.01478 [astro-ph.CO]].
  10. Md. R. Haque, D. Maity, T. Paul and L. Sriramkumar, Decoding the phases of early and late time reheating through imprints on primordial gravitational waves, Phys. Rev. D 104, 063513 (2021) [arXiv:2105.09242 [astro-ph.CO]].
  11. H. V. Ragavendra, L. Sriramkumar and J. Silk, Could PBHs and secondary GWs have originated from squeezed initial states?, JCAP 2105, 010 (2021) [arXiv:2011.09938 [astro-ph.CO]].
  12. H. V. Ragavendra, P. Saha, L. Sriramkumar and J. Silk, Primordial black holes and secondary gravitational waves from ultra slow roll and punctuated inflation, Phys. Rev. D 103, 083510 (2021) [arXiv:2008.12202 [astro-ph.CO]].
  13. M. Braglia, D. K. Hazra, F. Finelli, G. F. Smoot, L. Sriramkumar and A. A. Starobinsky, Generating PBHs and small-scale GWs in two-field models of inflation, JCAP 2008, 001 (2020) [arXiv: 2005.02895 [astro-ph.CO]].
  14. P. Saha, S. Anand and L. Sriramkumar, Accounting for the time evolution of the equation of state parameter during reheating, Phys. Rev. D 102, 103511 (2020) [arXiv:2005.01874 [astro-ph.CO]].
  15. M. Braglia, D. K. Hazra, L. Sriramkumar and F. Finelli, Generating primordial features at large scales in two field models of inflation, JCAP 2008, 025 (2020) [arXiv:2004.00672 [astro-ph.CO]].
  16. D. Nandi and L. Sriramkumar, Can non-minimal coupling restore the consistency condition in bouncing universes?, Phys. Rev. D 101, 043506 (2020) [arXiv:1904.13254 [gr-qc]].
  17. R. N. Raveendran and L. Sriramkumar, Viable scalar spectral tilt and tensor-to-scalar ratio in near-matter bounces, Phys. Rev. D 100, 083523 (2019) [arXiv:1812.06803 [astro-ph.CO]].
  18. R. N. Raveendran and L. Sriramkumar, Primordial features from ekpyrotic bounces, Phys. Rev. D 99, 043527 (2019) [arXiv:1809.03229 [astro-ph.CO]].
  19. D. Chowdhury, L. Sriramkumar and M. Kamionkowski, Cross-correlations between scalar perturbations and magnetic fields in bouncing universes, JCAP 1901, 048 (2019) [arXiv:1807.05530v2 [astro-ph.CO]].
  20. D. Chowdhury, L. Sriramkumar and M. Kamionkowski, Enhancing the cross-correlations between magnetic fields and scalar perturbations through parity violation, JCAP 1810, 031 (2018) [arXiv:1807.07477v2 [astro-ph.CO]].
  21. R. N. Raveendran, D. Chowdhury and L. Sriramkumar, Viable tensor-to-scalar ratio in a symmetric matter bounce, JCAP 1801, 030 (2018) [arXiv:1703.10061 [gr-qc]].
  22. D. J. Stargen, N. Kajuri and L. Sriramkumar, Response of a rotating detector coupled to a polymer quantized field, Phys. Rev. D 96, 066002 (2017) [arXiv:1706.05834 [gr-qc]].
  23. R. N. Raveendran and L. Sriramkumar, Numerical evaluation of the tensor bispectrum in two field inflation, JCAP 1707, 035 (2017) [arXiv:1611.00473 [astro-ph.CO]].
  24. D. J. Stargen, V. Sreenath and L. Sriramkumar, Quantum-to-classical transition and imprints of wavefunction collapse in bouncing universes, Int. J. Mod. Phys. D 30, 2150049 (2021) [arXiv:1605.07311 [gr-qc]].
  25. D. Chowdhury, V. Sreenath and L. Sriramkumar, The scalar-scalar-tensor inflationary three-point function in the axion monodromy model, JCAP 1611, 041 (2016) [arXiv:1605.05292 [astro-ph.CO]].
  26. D. Chowdhury, L. Sriramkumar and R. K. Jain, Duality and the generation of magnetic fields in bouncing universes, Phys. Rev. D 94, 083512 (2016) [arXiv:1604.02143 [gr-qc]].
  27. D. J. Stargen, D. Kothawala and L. Sriramkumar, Moving mirrors and the fluctuation-dissipation theorem, Phys. Rev. D 94, 025040 (2016) [arXiv:1602.02526 [hep-th]].
  28. D. Chowdhury, V. Sreenath and L. Sriramkumar, The tensor bi-spectrum in a matter bounce, JCAP 1511, 002 (2015) [arXiv:1506.06475 [astro-ph.CO]].
  29. L. Sriramkumar, K. Atmjeet and R. K. Jain, Generation of scale invariant magnetic fields in bouncing universes, JCAP 1509, 010 (2015) [arXiv:1504.06853 [astro-ph.CO]].
  30. V. Sreenath, D. K. Hazra and L. Sriramkumar, On the scalar consistency relation away from slow roll, JCAP 1502, 029 (2015) [arXiv:1410.0252 [astro-ph.CO]].
  31. V. Sreenath and L. Sriramkumar, Examining the consistency relations describing the three-point functions involving tensors, JCAP 1410, 021 (2014) [arXiv:1406.1609 [astro-ph.CO]].
  32. J. Martin, L. Sriramkumar and D. K. Hazra, Sharp inflaton potentials and bi-spectra: Effects of smoothening the discontinuity, JCAP 1409, 039 (2014) [arXiv:1404.6093 [astro-ph.CO]].
  33. V. Sreenath, R. Tibrewala and L. Sriramkumar, Numerical evaluation of the three-point scalar-tensor cross-correlations and the tensor bi-spectrum, JCAP 1312, 037 (2013) [arXiv:1309.7169 [astro-ph.CO]].
  34. D. K. Hazra, L. Sriramkumar and J. Martin, BINGO: A code for the efficient computation of the scalar bi-spectrum, JCAP 1305, 026, (2013) [arXiv:1201.0926 [astro-ph.CO]].
  35. M. Aich, D. K. Hazra, L. Sriramkumar and T. Souradeep, Oscillations in the inflaton potential: Complete numerical treatment and comparison with the recent and forthcoming CMB datasets, Phys. Rev. D 87, 083526 (2013) [arXiv:1106.2798 [astro-ph.CO]].
  36. D. K. Hazra, J. Martin and L. Sriramkumar, Scalar bi-spectrum during preheating in single field inflationary models, Phys. Rev. D 86, 063523 (2012) [arXiv:1206.0442].
  37. J. Martin and L. Sriramkumar, The scalar bi-spectrum in the Starobinsky model: The equilateral case, JCAP 1201, 008 (2012) [arXiv:1109.5838 [astro-ph.CO]].
  38. R. K. Jain, P. Chingangbam and L. Sriramkumar, Reheating in tachyonic inflationary models: Effects on the large scale curvature perturbations, Nucl. Phys. B 852, 366 (2011) [arXiv:0902.1067 [astro-ph.CO]].
  39. S. Gutti, S. Kulkarni and L. Sriramkumar, Modified dispersion relations and the response of the rotating Unruh-DeWitt detector, Phys. Rev. D 83, 064011 (2011) [arXiv:1005.1807 [gr-qc]].
  40. D. K. Hazra, M. Aich, R. K. Jain, L. Sriramkumar and T. Souradeep, Primordial features due to a step in the inflaton potential, JCAP 1010, 008 (2010) [arXiv:1005.2175 [astro-ph.CO]].
  41. R. K. Jain, P. Chingangbam, L. Sriramkumar and T. Souradeep, The tensor-to-scalar ratio in punctuated inflation, Phys. Rev. D 82, 023509 (2010) [arXiv:0904.2518 [astro-ph.CO]].
  42. S. Unnikrishnan and L. Sriramkumar, A note on perfect scalar fields, Phys. Rev. D 81, 103511 (2010) [arXiv:1002.0820 [astro-ph.CO]].
  43. D. A. Kothawala, L. Sriramkumar, S. Shankaranarayanan and T. Padmanabhan, Path integral duality modified propagators in spacetimes with constant curvature, Phys. Rev. D 80, 044005 (2009) [arXiv:0904.3217 [hep-th]].
  44. R. K. Jain, P. Chingangbam, J.-O. Gong, L. Sriramkumar and T. Souradeep, Punctuated inflation and the low CMB multipoles, JCAP 0901, 009 (2009) [arXiv:0809.3915 [astro-ph]].
  45. D. A. Kothawala, S. Shankaranarayanan and L. Sriramkumar, Quantum gravitational corrections to the stress-energy tensor around the BTZ black hole, JHEP 0809, 095 (2008) [arXiv:0801.0225 [hep-th]].
  46. S. Sarkar, S. Shankaranarayanan and L. Sriramkumar, Sub-leading contributions to the black hole entropy in the brick wall approach, Phys. Rev. D 78, 024003 (2008) [arXiv:0710.2013 [gr-qc]].
  47. R. K. Jain, P. Chingangbam and L. Sriramkumar, On the evolution of tachyonic perturbations at super-Hubble scales, JCAP 0710, 003 (2007) [arXiv:astro-ph/0703762].
  48. H. K. Jassal and L. Sriramkumar, Entropy of BTZ black strings in the brick wall approach, Class. Quantum Grav. 24, 2589 (2007) [arXiv:gr-qc/0611102].
  49. L. Sriramkumar and S. Shankaranarayanan, Path integral duality and Planck scale corrections to the primordial spectrum in exponential inflation, JHEP 0612, 050 (2006) [arXiv:hep-th/0608224].
  50. L. Sriramkumar and T. Padmanabhan, Initial state of matter fields and trans-Planckian physics: Can CMB observations disentangle the two?, Phys. Rev. D 71, 103512 (2005) [arXiv:gr-qc/0408034].
  51. S. Shankaranarayanan and L. Sriramkumar, Trans-Planckian corrections to the primordial spectrum in the infra-red and the ultra-violet, Phys. Rev. D 70, 123520 (2004) [arXiv:hep-th/0403236].
  52. L. Sriramkumar, Interpolating between the Bose-Einstein and the Fermi-Dirac distributions in odd dimensions, Gen. Rel. Grav. 35, 1699 (2003) [arXiv:gr-qc/0212084].
  53. L. Sriramkumar, Odd statistics in odd dimensions for odd couplings, Mod. Phys. Lett. A 17, 1059 (2002) [arXiv:gr-qc/0206048].
  54. L. Sriramkumar, Fluctuations in the current and energy densities around a magnetic-flux-carrying cosmic string, Class. Quantum Grav. 18, 1015 (2001) [arXiv:gr-qc/0011074].
  55. G. Gour and L. Sriramkumar, Will small particles exhibit Brownian motion in the quantum vacuum?, Found. Phys. 29, 1917 (1999) [arXiv:quant-ph/9808032].
  56. L. Sriramkumar, On the response of detectors in classical electromagnetic backgrounds, Mod. Phys. Lett. A 14, 1869 (1999) [arXiv:hep-th/9811250].
  57. K. Srinivasan, L. Sriramkumar and T. Padmanabhan, Hypothesis of path integral duality II: Corrections to quantum field theoretic results, Phys. Rev. D 58, 044009 (1998) [arXiv:gr-qc/9710104].
  58. K. Srinivasan, L. Sriramkumar and T. Padmanabhan, Possible quantum interpretation of certain power spectra in classical field theory, Int. J. Mod. Phys. D 6, 607 (1997) [arXiv:gr-qc/9606017].
  59. K. Srinivasan, L. Sriramkumar and T. Padmanabhan, Plane waves viewed from an accelerated frame: Quantum physics in a classical setting, Phys. Rev. D 56, 6692 (1997).
  60. L. Sriramkumar, Limits on the validity of the semiclassical theory - A minisuperspace example, Int. J. Mod. Phys. D 6, 363 (1997) [arXiv:gr-qc/9505037].
  61. L. Sriramkumar, R. Mukund and T. Padmanabhan, Non-trivial classical backgrounds with vanishing quantum corrections, Phys. Rev. D 55, 6147 (1997) [arXiv:hep-th/9703034].
  62. L. Sriramkumar and T. Padmanabhan, Does a nonzero tunneling probability imply particle production in time-independent classical electromagnetic backgrounds?, Phys. Rev. D 54, 7599 (1996) [arXiv:hep-th/9604111].
  63. L. Sriramkumar and T. Padmanabhan, Finite-time response of inertial and uniformly accelerated Unruh-DeWitt detectors, Class. Quantum Grav. 13, 2061 (1996) [arXiv:gr-qc/9408037].

As reviews

  1. H. V. Ragavendra and L. Sriramkumar, Observational imprints of enhanced scalar power on small scales in ultra slow roll inflation and associated non-Gaussianities, Galaxies 11, 34 (2023) [arXiv:2301.08887 [astro-ph.CO]].
  2. L. Sriramkumar, An introduction to inflation and cosmological perturbation theory, Curr. Sci. 97, 868 (2009) [arXiv:0904.4584 [astro-ph.CO]].
  3. L. Sriramkumar and T. Padmanabhan, Probes of the vacuum structure of quantum fields in classical backgrounds, Int. J. Mod. Phys. D 11, 1 (2002) [arXiv:gr-qc/9903054].

Publications in proceedings of conferences

  1. H. V. Ragavendra, D. Chowdhury and L. Sriramkumar, Unique contributions to the scalar bispectrum in `just enough inflation', Proceedings of the Workshop on Frontiers in High Energy Physics (University of Hyderabad, Hyderabad, October 14-17, 2019), Eds. A. Giri and R. Mohanta (Springer, Singapore, 2020), pp. 39-47 [arXiv:1906.03942 [astro-ph.CO]].
  2. L. Sriramkumar, Primordial gravitational waves, BICEP2 and beyond, in Proceedings of the International Workshop on Unification and Cosmology after Higgs Discovery and BICEP2 (Department of Physics, Panjab University, Chandigarh, May 13-15, 2014), Pramana 86, 325-333 (2016).
  3. D. A. Kothawala, S. Shankaranarayanan and L. Sriramkumar, Quantum gravitational corrections to the propagator in spacetimes with constant curvature, in Proceedings of the Twelfth Marcel Grossmann Meeting on General Relativity (UNESCO Headquarters, Paris, France, July 12-18, 2009), Eds. T. Damour, R. Jantzen and R. Ruffini (World Scientific, Singapore, 2012), pp. 2426-2428 [arXiv:1002.1132 [hep-th]].
  4. S. Sarkar, S. Shankaranarayanan and L. Sriramkumar, Corrections to the Bekenstein-Hawking entropy in the brick wall approach, in Proceedings of the Meeting on Black Holes in General Relativity and String Theory (Veli Losinj, Croatia, August 24-30, 2008), PoS (BHs, GR and Strings) 035 (2009).
  5. S. Shankaranarayanan and L. Sriramkumar, Planck scale effects and the suppression of power on the large scales in the primordial spectrum, in Proceedings of the Tenth International Symposium on Particles, Strings and Cosmology (Northeastern University, Boston, U.S.A., August 16-22, 2004), Eds. G. Alverson, E. Barberis, P. Nath and M. T. Vaughn (World Scientific, Singapore, 2004), pp. 38-42 [arXiv:hep-th/0410072].
  6. L. Sriramkumar, T. Padmanabhan and R. Mukund, Classical backgrounds with vanishing effective Lagrangians, in Proceedings of the Eighth Marcel Grossmann Meeting on General Relativity (Hebrew University, Jerusalem, Israel, June 22-27, 1997), Ed. T. Piran (World Scientific, Singapore, 1999), pp. 833-835.

Unpublished article

  1. L. Sriramkumar, Superfluid helicity and vortex reconnections.

Other articles

  1. L. Sriramkumar, What do detectors detect?, in Gravity and the Quantum, Eds. J. S. Bagla and S. Engineer (Springer, Berlin, 2017), pp. 457-478 [arXiv:1612.08579 [gr-qc]].
  2. L. Sriramkumar, On the generation and evolution of perturbations during inflation and reheating, in Vignettes in Gravitation and Cosmology, Eds. L. Sriramkumar and T. R. Seshadri (World Scientific, Singapore, 2012), pp. 207-249.

Books edited

  1. L. Sriramkumar and T. R. Seshadri (Editors), Vignettes in Gravitation and Cosmology (World Scientific, Singapore, 2012).

Popular articles

  1. L. Sriramkumar, How Stephen Hawking’s discovery has changed the way we look at black holes, The New Indian Express, Edex Live, March 14, 2018.
  2. L. Sriramkumar, Ripples in spacetime - A new window to the universe, The Fifth Estate, August 22, 2016.
  3. L. Sriramkumar and T. Souradeep, A glimpse of the early universe through BICEP2, The Hindu Online, April 1, 2014.