Horizon feedback inflation

Fairbairn, Malcolm; Markkanen, Tommi; Roman, David Rodriguez

doi:10.1140/epjc/s10052-018-5830-0

Cited by 10 publications

(9 citation statements)

References 84 publications

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“…In extended work it would be interesting to study the effect of a number of alternative couplings on the formation of post-inflationary spectator condensates, such as e.g. trilinear couplings (as in the case of the Higgs [26]) and couplings of multiple fields to the inflationary sector (as in 'M-flation' [27] or the newly proposed model of 'Horizon Feedback Inflation' [28]). The abundance of post-inflationary condensates can also be known to affect various models of dark energy [29], dark matter [30], and the reheating decay efficiency of the inflaton through Higgs thermal blocking [31].…”

Section: Discussionmentioning

confidence: 99%

Multiple spectator condensates from inflation

Hardwick

2018

J. Cosmol. Astropart. Phys.

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We investigate the development of spectator (light test) field condensates due to their quantum fluctuations in a de Sitter inflationary background, making use of the stochastic formalism to describe the system. In this context, a condensate refers to the typical field value found after a coarse-graining using the Hubble scale H, which can be essential to seed the initial conditions required by various post-inflationary processes. We study models with multiple coupled spectators and for the first time we demonstrate that new forms of stationary solution exist (distinct from the standard exponential form) when the potential is asymmetric. Furthermore, we find a critical value for the inter-field coupling as a function of the number of fields above which the formation of stationary condensates collapses to H. Considering some simple two-field example potentials, we are also able to derive a lower limit on the coupling, below which the fluctuations are effectively decoupled, and the standard stationary variance formulae for each field separately can be trusted. These results are all numerically verified by a new publicly available python class (nfield) to solve the coupled Langevin equations over a large number of fields, realisations and timescales. Further applications of this new tool are also discussed.

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Section: Discussionmentioning

confidence: 99%

Multiple spectator condensates from inflation

Hardwick

2018

J. Cosmol. Astropart. Phys.

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“…Technically, the effect of a positive Λ is to replace SL(2, C) with a quantum deformation of SL(2, C). The mathematics for implementing this deformation has been developed [110,111] and the Spinfoam amplitude with the cosmological constant has also been defined [112,113]. The transition amplitudes of the theory with a quantum deformation of SL(2, C) are finite, and the classical limit of their vertex amplitude is still given by Eq.…”

Section: Cosmological Constant and Ir Finitenessmentioning

confidence: 99%

“…The number of simplices that feature in the underlying 4-geometries provides a mathematically natural expansion parameter to calculate transition amplitudes. These amplitudes are UV finite to any order in this expansion [92][93][94][95] and, in presence of a positive cosmological constant, there is an elegant procedure involving a quantum deformation of SL(2, C) (the double cover of the local Lorentz group) that provides a natural infrared regulator [112,113]. Finally, in III C we summarized the construction of n-point functions in the semi-classical limit of this model.…”

Section: A Summarymentioning

confidence: 99%

From general relativity to quantum gravity

Ashtekar¹,

Reuter

Rovelli

Mathematical Problems in Theoretical Physics

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In general relativity (GR), spacetime geometry is no longer just a background arena but a physical and dynamical entity with its own degrees of freedom. We present an overview of approaches to quantum gravity in which this central feature of GR is at the forefront. However, the short distance dynamics in the quantum theory are quite different from those of GR and classical spacetimes and gravitons emerge only in a suitable limit. Our emphasis is on communicating the key strategies, the main results and open issues. In the spirit of this volume, we focus on a few avenues that have led to the most significant advances over the past 2-3 decades. 1

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“…For several decades the leading hypothesis for the earliest stages of the evolution of the Universe has contained a period of cosmological Inflation where the scale factor expanded exponentially, solving many cosmological problems and explaining the origins of astrophysical structure formation across many orders of magnitude in physical scale [21][22][23]. While Inflation has its own fine tuning problems (see attempts to address and recast some of these here [24]), there are not many compelling alternatives to Inflation which have a simpler or even equally simple mathematical consistency.…”

Section: Introductionmentioning

confidence: 99%

Gravitationally produced top quarks and the stability of the electroweak vacuum during inflation

Roman

Fairbairn

2019

Phys. Rev. D

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In the standard model the (Brout-Englert-)Higgs quartic coupling becomes negative at high energies rendering our current electroweak vacuum metastable, but with an instability timescale much longer than the age of the Current Universe. During cosmological Inflation, unless there is a non-minimal coupling to gravity, the Higgs field is pushed away from the origin of its potential due to quantum fluctuations. It is therefore a mystery how we have remained in our current vacuum if we went through such a period of Inflation. In this work we study the effect of top quarks created gravitationally during Inflation and their effect upon the Higgs potential using only General Relativity with minimal couplings and Standard Model particle physics. We show how the evolution of the Higgs field during Inflation is modified coming to the conclusion that this effect is non negligible for scales of Inflation close to or larger than the stability scale but small for scales where the Higgs is stable. Also, we briefly discuss the effect of other fermions to the Higgs instability.

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Horizon feedback inflation

Cited by 10 publications

References 84 publications

Multiple spectator condensates from inflation

Multiple spectator condensates from inflation

From general relativity to quantum gravity

Gravitationally produced top quarks and the stability of the electroweak vacuum during inflation

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