Higgsed Gauge-flation

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Multi-field inflation with a curved scalar geometry has been found to support background trajectories that violate the slow-roll, slow-turn conditions and thus have the potential to evade the swampland constraints. In order to understand how generic this novel behaviour is and what conditions lead to it, we perform a classification of dynamical attractors of two-field inflation that are of the scaling type. Scaling solutions form a oneparameter generalization of De Sitter solutions with a constant value of the first Hubble flow parameter and, as we argue and demonstrate, form a natural starting point for the study of non-slow-roll slow-turn behaviour.All scaling solutions can be classified as critical points of a specific dynamical system. We recover known multi-field inflationary attractors as approximate scaling solutions and classify their stability using dynamical system techniques. In particular, we discover that dynamical bifurcations play an integral role in the transition between geodesic and nongeodesic motion and discuss the ability of scaling solutions to describe realistic multi-field models. We revisit the criteria for background stability and show cases where the usual criteria found in the literature do not capture the background evolution of the system. arXiv:1903.06116v2 [hep-th] 29 Jul 2019 Contents 7 Summary and Discussion 32 A Coordinate transformations and isometries 34 B Hurwitz-Routh stability criterion 34 C Bifurcations in dynamical systems 35 1 There has been a growing interesting for inflationary models involving gauge fields (see e.g. Refs. [13-17]); however, in such cases, a scalar degree of freedom that takes the role of the inflaton can be identified. 2 There are a few examples in the literature which admit general analytical solutions [18-28]. These are completely integrable systems where the mini-super Lagrangian has Noether symmetries, and have been classified in Refs. [29-31].

Section: Critical Points Analysismentioning

confidence: 99%

Scaling attractors in multi-field inflation

Christodoulidis

Roest

Sfakianakis

2019

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“…The tensor tilt n (vac) T is thus always negative and has a typical magnitude O(10 −2 ) or smaller. On the contrary, the spectrum of gravitational waves that are sourced through axion-gauge dynamics or higherorder gauge interactions can have a blue tilt [29,53]. In the specific case of Type I potentials, n power T is given by Eq.…”

Section: Type I and Ii Potentialsmentioning

confidence: 99%

Tensor spectra templates for axion-gauge fields dynamics during inflation

Fujita

Sfakianakis

Shiraishi

2019

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SU (2) gauge fields can generate large gravitational waves during inflation, if they are coupled to an axion which can be either the inflaton or a spectator field. The shape of the produced tensor power spectrum P h depends on the form of the axion potential. We derive analytic expressions and provide general templates for P h for various types of the spectator axion potential. Furthermore, we explore the detectability of the oscillatory feature, which is present in P h in the case of an axion monodromy model, by possible future CMB B-mode polarization observations.

“…Further implications of such a coupling to SM gauge groups are the presence of primordial magnetic fields and even a possible contribution to baryogenesis, see e.g. [52][53][54] for recent works. However it is also possible to imagine more complicated scenarios.…”

Section: µ-Type Distortions In the Cmbmentioning

confidence: 99%

Primordial gravitational waves for universality classes of pseudoscalar inflation

Domcke

Pieroni

Binétruy

2016

125

158

Current bounds from the polarization of the CMB predict the scale-invariant gravitational wave (GW) background of inflation to be out of reach for upcoming GW interferometers. This prospect dramatically changes if the inflaton is a pseudoscalar, in which case its generic coupling to any abelian gauge field provides a new source of GWs, directly related to the dynamics of inflation. This opens up new ways of probing the scalar potential responsible for cosmic inflation. Dividing inflation models into universality classes, we analyze the possible observational signatures. One of the most promising scenarios is Starobinsky inflation, which may lead to observational signatures both in direct GW detection as well as in upcoming CMB detectors. In this case, the complementarity between the CMB and direct GW detection, as well as the possibility of a multi-frequency analysis with upcoming ground and space based GW interferometers, may provide a first clue to the microphysics of inflation.