Warm inflation

In physical cosmology, warm inflation is one of two dynamical realizations of cosmological inflation. The other is the standard scenario,[1][2][3] sometimes called cold inflation.[4]

In warm inflation radiation production occurs concurrently with inflationary expansion. This is consistent with the conditions necessary for inflation as given by the Friedmann equations of general relativity, which simply require that the vacuum energy density dominates the energy content of the universe at time of inflation, and so does not prohibit some radiation to be present. As such the most general picture of inflation would include a radiation energy density component. The presence of radiation during inflation implies the inflationary phase could smoothly end into a radiation-dominated era without a distinctively separate reheating phase,[5] thus providing a solution to the graceful exit problem of inflation.[1][2][6][7][8]


  1. ^ a b Guth, Alan H. (15 January 1981). "Inflationary universe: A possible solution to the horizon and flatness problems". Physical Review D. American Physical Society (APS). 23 (2): 347–356. doi:10.1103/physrevd.23.347. ISSN 0556-2821.
  2. ^ a b Linde, A.D. (1982). "A new inflationary universe scenario: A possible solution of the horizon, flatness, homogeneity, isotropy and primordial monopole problems". Physics Letters B. Elsevier BV. 108 (6): 389–393. doi:10.1016/0370-2693(82)91219-9. ISSN 0370-2693.
  3. ^ Albrecht, Andreas; Steinhardt, Paul J. (26 April 1982). "Cosmology for Grand Unified Theories with Radiatively Induced Symmetry Breaking". Physical Review Letters. American Physical Society (APS). 48 (17): 1220–1223. doi:10.1103/physrevlett.48.1220. ISSN 0031-9007.
  4. ^ Berera, Arjun (30 October 1995). "Warm Inflation". Physical Review Letters. American Physical Society (APS). 75 (18): 3218–3221. doi:10.1103/physrevlett.75.3218. ISSN 0031-9007. PMID 10059529. S2CID 39966621.
  5. ^ Berera, Arjun (15 March 1997). "Interpolating the stage of exponential expansion in the early universe: Possible alternative with no reheating". Physical Review D. American Physical Society (APS). 55 (6): 3346–3357. arXiv:hep-ph/9612239. doi:10.1103/physrevd.55.3346. ISSN 0556-2821. S2CID 2195582.
  6. ^ Albrecht, Andreas; Steinhardt, Paul J.; Turner, Michael S.; Wilczek, Frank (17 May 1982). "Reheating an Inflationary Universe". Physical Review Letters. American Physical Society (APS). 48 (20): 1437–1440. doi:10.1103/physrevlett.48.1437. ISSN 0031-9007.
  7. ^ Dolgov, A.D.; Linde, A.D. (1982). "Baryon asymmetry in the inflationary universe". Physics Letters B. Elsevier BV. 116 (5): 329–334. doi:10.1016/0370-2693(82)90292-1. ISSN 0370-2693.
  8. ^ Abbott, L.F.; Farhi, Edward; Wise, Mark B. (1982). "Particle production in the new inflationary cosmology". Physics Letters B. Elsevier BV. 117 (1–2): 29–33. doi:10.1016/0370-2693(82)90867-x. ISSN 0370-2693.