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Title: Effects of thermal fluctuations on thermal inflation

Abstract

The mechanism of thermal inflation, a relatively short period of accelerated expansion after primordial inflation, is a desirable ingredient for a certain class of particle physics models if they are not to be in contention with the cosmology of the early Universe. Though thermal inflation is most simply described in terms of a thermal effective potential, a thermal environment also gives rise to thermal fluctuations that must be taken into account. We numerically study the effects of these thermal fluctuations using lattice simulations. We conclude that though they do not ruin the thermal inflation scenario, the phase transition at the end of thermal inflation proceeds through phase mixing and is therefore not accompanied by the formations of bubbles nor appreciable amplitude of gravitational waves.

Authors:
 [1];  [2];  [3];  [4];  [5]
  1. Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto 606-8502 (Japan)
  2. Department of Physics, Graduate School of Science, The University of Tokyo, Tokyo 113-0033 (Japan)
  3. (RESCEU), Graduate School of Science, The University of Tokyo, Tokyo 113-0033 (Japan)
  4. Research Center for the Early Universe (RESCEU), Graduate School of Science, The University of Tokyo, Tokyo 113-0033 (Japan)
  5. (Kavli IPMU), WPI, TODIAS, The University of Tokyo, Kashiwa, Chiba, 277-8568 (Japan)
Publication Date:
Sponsoring Org.:
SCOAP3, CERN, Geneva (Switzerland)
OSTI Identifier:
22454523
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Cosmology and Astroparticle Physics; Journal Volume: 2015; Journal Issue: 03; Other Information: PUBLISHER-ID: JCAP03(2015)024; OAI: oai:repo.scoap3.org:9549; Article funded by SCOAP3. Content from this work may be used under the terms of the Creative Commons Attribution 3.0 License. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; AMPLITUDES; COSMOLOGICAL INFLATION; COSMOLOGY; FLUCTUATIONS; GRAVITATIONAL WAVES; LATTICE FIELD THEORY; NUMERICAL ANALYSIS; PHASE TRANSFORMATIONS; POTENTIALS; UNIVERSE

Citation Formats

Hiramatsu, Takashi, Miyamoto, Yuhei, Research Center for the Early Universe, Yokoyama, Jun’ichi, and Kavli Institute for the Physics and Mathematics of the Universe. Effects of thermal fluctuations on thermal inflation. United States: N. p., 2015. Web. doi:10.1088/1475-7516/2015/03/024.
Hiramatsu, Takashi, Miyamoto, Yuhei, Research Center for the Early Universe, Yokoyama, Jun’ichi, & Kavli Institute for the Physics and Mathematics of the Universe. Effects of thermal fluctuations on thermal inflation. United States. doi:10.1088/1475-7516/2015/03/024.
Hiramatsu, Takashi, Miyamoto, Yuhei, Research Center for the Early Universe, Yokoyama, Jun’ichi, and Kavli Institute for the Physics and Mathematics of the Universe. 2015. "Effects of thermal fluctuations on thermal inflation". United States. doi:10.1088/1475-7516/2015/03/024.
@article{osti_22454523,
title = {Effects of thermal fluctuations on thermal inflation},
author = {Hiramatsu, Takashi and Miyamoto, Yuhei and Research Center for the Early Universe and Yokoyama, Jun’ichi and Kavli Institute for the Physics and Mathematics of the Universe},
abstractNote = {The mechanism of thermal inflation, a relatively short period of accelerated expansion after primordial inflation, is a desirable ingredient for a certain class of particle physics models if they are not to be in contention with the cosmology of the early Universe. Though thermal inflation is most simply described in terms of a thermal effective potential, a thermal environment also gives rise to thermal fluctuations that must be taken into account. We numerically study the effects of these thermal fluctuations using lattice simulations. We conclude that though they do not ruin the thermal inflation scenario, the phase transition at the end of thermal inflation proceeds through phase mixing and is therefore not accompanied by the formations of bubbles nor appreciable amplitude of gravitational waves.},
doi = {10.1088/1475-7516/2015/03/024},
journal = {Journal of Cosmology and Astroparticle Physics},
number = 03,
volume = 2015,
place = {United States},
year = 2015,
month = 3
}
  • The mechanism of thermal inflation, a relatively short period of accelerated expansion after primordial inflation, is a desirable ingredient for a certain class of particle physics models if they are not to be in contention with the cosmology of the early Universe. Though thermal inflation is most simply described in terms of a thermal effective potential, a thermal environment also gives rise to thermal fluctuations that must be taken into account. We numerically study the effects of these thermal fluctuations using lattice simulations. We conclude that though they do not ruin the thermal inflation scenario, the phase transition at themore » end of thermal inflation proceeds through phase mixing and is therefore not accompanied by the formations of bubbles nor appreciable amplitude of gravitational waves.« less
  • The effects of thermal fluctuations on the evolution of a weakly coupled scalar field in the preinflationary phase of a model of new inflation are studied. Limits on the coupling constants are derived below which the effects of thermal fluctuations are negligible. The stochastic approach to inflation is extended to cover a situation in which spatial gradient terms and acceleration terms in the equation of motion of the scalar field dominate.
  • The effects of thermal fluctuations on the evolution of the scalar field in a preinflationary period are explored numerically to complement a previous analytical investigation. The analysis is applicable to a weakly coupled scalar field in a double-well potential in new inflation. A critical value of the strength of the coupling to the thermal bath is found, above which thermal fluctuations do not allow the inflationary period to begin. The evolution of the scalar field is followed until the onset of the inflationary period.
  • We consider primordial fluctuations in thermal inflation scenario. Since the thermal inflation drives about 10 e-folds after the standard inflation, the time of horizon-exit during inflation corresponding to the present observational scale shifts toward the end of inflation. It generally makes the primordial power spectrum more deviated from a scale-invariant one and hence renders some models inconsistent with observations. We present a mechanism of generating the primordial curvature perturbation at the end of thermal inflation utilizing a fluctuating coupling of a flaton field with the fields in thermal bath. We show that, by adopting the mechanism, some inflation models canmore » be liberated even in the presence of the thermal inflation. We also discuss non-Gaussianity in the mechanism and show that large non-Gaussianity can be generated in this scenario.« less
  • This paper discusses models of inflation based on global supersymmetry. It is shown that there are parameter ranges, consistent with observational constraints, for which warm inflation occurs and supergravity effects can be neglected. There is no need for any fine tuning of parameters. The thermal corrections to the inflaton potential are calculated and it is shown that they do not alter the warm inflationary evolution.