Thermal particle creation in cosmological spacetimes: A stochastic approach

Koks, Don; Hu, B. L.; Matacz, Andrew; Raval, Alpan

doi:10.1103/physrevd.56.4905

Cited by 18 publications

(19 citation statements)

References 36 publications

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“…We stress that the production is, however, much stronger than that obtained in previous studies where the scalar factor evolves monotonically [19]. This mild situation changes dramatically when a non-minimal coupling is introduced.…”

Section: Scalar Fieldscontrasting

confidence: 50%

“…Nonetheless, in either case, gauge-invariant quantities such as the radiation energy density, are unaffected. In a FLRW background, the Ricci tensor is diagonal, which together with the gauge choice (20) and expansion over eigenfunctions, ensures the decoupling of the set of equations (19). We can reduce the system to a set of decoupled Mathieu equations.…”

Section: The Vector Casementioning

confidence: 99%

See 1 more Smart Citation

Erratum: Geometric reheating after inflation [Phys. Rev. D58, 021302 (1998)]

Bassett¹,

Liberati²

1999

Phys. Rev. D

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Inflationary reheating via resonant production of non-minimally coupled scalar particles with only gravitational coupling is shown to be extremely strong, exhibiting a negative coupling instability for ξ < 0 and a wide resonance decay for ξ ≫ 1. Since non-minimal fields are generic after renormalization in curved spacetime, this offers a new paradigm in reheating -one which naturally allows for efficient production of the massive bosons needed for GUT baryogenesis. We also show that both vector and tensor fields are produced resonantly during reheating, extending the previously known correspondences between bosonic fields of different spin during preheating.

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Section: Scalar Fieldscontrasting

confidence: 50%

Section: The Vector Casementioning

confidence: 99%

Erratum: Geometric reheating after inflation [Phys. Rev. D58, 021302 (1998)]

Bassett¹,

Liberati²

1999

Phys. Rev. D

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“…(2) corresponds to λ Ψ -independent stochastic evolution (ξ(t) Gaussian white noise) describing the effect of multiple fields in the strong coupling limit (in which case q = 0, as there is no periodic component). This form of the potential also models the backreaction of quantum fluctuations on the mean periodic evolution of φ (q = 0) in the case where the Ψ are absent [22,20]. Using spectral theory it was shown [21] that the stability bands essentially disappear in the case of stochastic potentials F .…”

mentioning

confidence: 99%

Inflationary Reheating in Grand Unified Theories

Bassett

Tamburini

1998

Phys. Rev. Lett.

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Grand unified theories may display multiply interacting fields with strong coupling dynamics. This poses two new problems: (1) what is the nature of chaotic reheating after inflation, and (2) how is reheating sensitive to the mass spectrum of these theories ? We answer these questions in two interesting limiting cases and demonstrate an increased efficiency of reheating which strongly enhances non-thermal topological defect formation, including monopoles and domain walls. Nevertheless, the large fluctuations may resolve this monopole problem via a modified Dvali-Liu-Vachaspati mechanism in which non-thermal destabilsation of discrete symmetries occurs at reheating. An ideal inflationary scenario should arise naturally from within supergravity or a Grand Unified Theory (GUT) without fine-tuning. It should solve the plethora of problems of standard cosmology while simultaneously diltuting the monopoles inevitably produced due to the homotopic content π 2 (G/U (1)) ≃ π 1 (U (1)) ≃ Z of the standard model. Significant progress has been made within GUT's and supersymmetric theories towards this utopic vision [1,2]. However, the issue of reheating after inflation in these theories, where the universe is revived, phoenix-like, from the frozen vacuum state, has remained relatively unexplored [3]. This is precisely one area where the full symmetry and particle content of the underlying theory is likely to be crucial. SISSA-42Indeed reheating poses a severe threat to the simple ideal presented above since non-perturbative effects are typically dominant [4][5][6][7]. Reheating is therefore not a minor phase at the end of inflation, of little dynamical interest. The large quantum fluctuations allow for GUT baryogenesis [8,5] and, as pointed out by Kofman et al [4], may cause the monopole and domain wall problems to reappear due to non-thermal symmetry restoration. This last possibility is actually rather difficult in simple models of reheating with only two fields [6]. As we shall show, however, this situation changes dramatically in the case of multiple fields, relevant for GUT models.The main motivation of this work then is to understand what new effects multiple fields have on reheating. This issue encompasses two particularly interesting unknowns. (i) The nature of reheating at strong coupling when the fields evolve chaotically. This is relevant for GUT's with divergent UV fixed points [9,10] and models such as softly broken Seiberg-Witten inflation [11] where reheating occurs in the strongly coupled, confining, regime. Setting aside the subtle issue of the quantum behaviour of gauge theories at strong coupling [12], in the two and three scalar-field cases studied so far, (classical) chaotic motion has been typical [13], especially at reheating. This chaotic evolution parallels results in the Einstein-Yang-Mills equations [14], semi-classical QCD and lattice gauge theory [15]. Thus a natural question is "what is the nature of chaotic reheating ?"The second issue is (ii) the sensitivity of reheating to the mass spectrum ...

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“…Both sets of modes (11) and (15) together with their complex conjugates are orthonormal and complete in the region to the right of the mirror.…”

Section: Preliminariesmentioning

confidence: 99%

“…It has to be mentioned that the view that the mechanism responsible for the thermal rates of the detector is intrinsically local and that thermality can be decoupled from the existence of the Rindler horizon was firmly advocated more than two decades ago by Hu and collaborators in a series of papers [12,13,14,15]. Their conclusion was based on a calculation of the thermal rates using the Feynman-Vernon influence functional method which relies entirely on local concepts and thus emphasizes the local nature of the effect.…”

Section: Introductionmentioning

confidence: 99%

Unruh effect without Rindler horizon

Nicolaevici¹

2015

Class. Quantum Grav.

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We investigate the Unruh effect for a massless scalar field in the two dimensional Minkowski space in the presence of a uniformly accelerated perfect mirror, with the trajectory of the mirror chosen in such a way that the mirror completely masks the Rindler horizon from the spacetime region of interest. We find that the characteristic thermodynamical properties of the effect remain unchanged, i.e. the response of a uniformly co-accelerated Unruh detector and the distribution of the Rindler particles retain their thermal form. However, since in this setup there are no unobserved degrees of freedom of the field, the thermal statistics of the Rindler particles is inconsistent with an initial pure vacuum, which leads us to reconsider the problem for the more physical case when the mirror is inertial in the past. In these conditions we find that the distribution of the Rindler particles is non-thermal even in the limit of infinite acceleration times, but an effective thermal statistics can be recovered provided that one restricts to the expectation values of smeared operators associated to finite norm Rindler states. We explain how the thermal statistics in our problem can be understood in analogy with that in the conventional version of the effect.

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Thermal particle creation in cosmological spacetimes: A stochastic approach

Cited by 18 publications

References 36 publications

Erratum: Geometric reheating after inflation [Phys. Rev. D58, 021302 (1998)]

Erratum: Geometric reheating after inflation [Phys. Rev. D58, 021302 (1998)]

Inflationary Reheating in Grand Unified Theories

Unruh effect without Rindler horizon

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