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The particle model building of cosmological collider physics often involves boost-breaking bilinear mixing between a heavy particle and the nearly massless inflaton mode. In cosmological correlators, such a mixing is obtained by taking a…

High Energy Physics - Theory · Physics 2025-11-13 Zhong-Zhi Xianyu , Jiaju Zang

We calculate the squeezed limit of the bispectrum produced by inflation with multiple light fields. To achieve this we allow for different horizon exit times for each mode and calculate the intrinsic field-space three-point function in the…

Cosmology and Nongalactic Astrophysics · Physics 2016-04-07 Zachary Kenton , David J. Mulryne

A scale-invariant universe can have a period of accelerated expansion at early times: inflation. We use a frame-invariant approach to calculate inflationary observables in a scale invariant theory of gravity involving two scalar fields -…

Cosmology and Nongalactic Astrophysics · Physics 2018-06-26 Pedro G. Ferreira , Christopher T. Hill , Johannes Noller , Graham G. Ross

We present a new, exact scalar field cosmology for which the spectrum of scalar (density) perturbations can be calculated exactly. We use this exact result to the probe the accuracy of approximate calculations of the perturbation spectrum.

Astrophysics · Physics 2009-10-28 Richard Easther

We consider the dynamics of massive spinning fields during inflation and the resulting signatures in the cosmological correlators of inflaton perturbations computed in the Poincar\'e patch of de Sitter space. There are (at least) two ways…

High Energy Physics - Theory · Physics 2025-10-13 Trevor Cheung , David Stefanyszyn

We study the curvaton scenario in supersymmetric framework paying particular attention to the fact that scalar fields are inevitably complex in supersymmetric theories. If there are more than one scalar fields associated with the curvaton…

High Energy Physics - Phenomenology · Physics 2009-11-10 Koichi Hamaguchi , Masahiro Kawasaki , Takeo Moroi , Fuminobu Takahashi

Prior to recombination, Silk damping causes the dissipation of energy from acoustic waves into the monopole of the Cosmic Microwave Background (CMB), resulting in spectral distortions. These can be used to probe the primordial scalar power…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-18 Sebastien Clesse , Björn Garbrecht , Yi Zhu

We present a new class of two-field inflationary attractor models, known as `shift-symmetric orbital inflation', whose behaviour is strongly multi-field but whose predictions are remarkably close to those of single-field inflation. In these…

Cosmology and Nongalactic Astrophysics · Physics 2020-07-29 Ana Achúcarro , Edmund J. Copeland , Oksana Iarygina , Gonzalo A. Palma , Dong-Gang Wang , Yvette Welling

The observed power spectrum of the cosmic microwave background (CMB) is consistent with inflationary cosmology, which predicts a nearly scale-invariant power spectrum of quantum fluctuations of the inflaton field as they exit the Hubble…

High Energy Physics - Theory · Physics 2007-05-23 Leonard Parker

Solid inflation is an effective field theory of inflation in which isotropy and homogeneity are accomplished via a specific combination of anisotropic sources (three scalar fields that individually break isotropy). This results in specific…

Cosmology and Nongalactic Astrophysics · Physics 2015-09-11 Nicola Bartolo , Marco Peloso , Angelo Ricciardone , Caner Unal

Motivated by the prospect of testing inflation from precision cosmic microwave background observations, we present analytic results for scalar and tensor perturbations in single-field inflation models based on the application of uniform…

Astrophysics · Physics 2009-11-07 Salman Habib , Katrin Heitmann , Gerard Jungman , Carmen Molina-Paris

Coupling between sub- and super-Hubble modes can affect the locally observed statistics of our universe. In the context of Quasi-Single Field Inflation, we can compute correlation functions and derive the influence of those unobservable…

Cosmology and Nongalactic Astrophysics · Physics 2018-05-23 Anne-Sylvie Deutsch

We study the general relation between the power spectrum and the squeezed limit of the bispectrum of the comoving curvature perturbation produced during single-field slow-roll inflation when the initial state is a general vacuum. Assuming…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-12 Jinn-Ouk Gong , Misao Sasaki

We show explicitly some exciting features of double-inflation: (i) it can often lead to strongly correlated adiabatic and entropy (isocurvature) power spectra. (ii) The two-field slow-roll consistency relations can be violated when the…

Astrophysics · Physics 2009-11-07 Shinji Tsujikawa , David Parkinson , Bruce A. Bassett

The computation of the spectrum of primordial perturbations, generated by a scalar field during the super-inflationary phase of Loop Quantum Cosmology, is revisited. The calculation is performed for two different cases. The first considers…

Astrophysics · Physics 2009-11-11 D. J. Mulryne , N. J. Nunes

A scenario with two subsequent periods of inflationary expansion in the very early universe is examined. The model is based on a potential motivated by symmetries being found in field theory at high energy. For various parameter sets of the…

Cosmology and Nongalactic Astrophysics · Physics 2016-01-13 Simon Schettler , Jurgen Schaffner-Bielich

A disformal coupling between two scalar fields is considered in the context of cosmological inflation. The coupling introduces novel derivative interactions mixing the kinetic terms of the fields but without introducing superluminal or…

Cosmology and Nongalactic Astrophysics · Physics 2016-05-23 Carsten van de Bruck , Tomi Koivisto , Chris Longden

Collisions between cosmic bubbles of different vacua are a generic feature of false vacuum eternal inflation scenarios. While previous studies have focused on the consequences of a single collision event in an observer's past, we begin here…

High Energy Physics - Theory · Physics 2013-05-30 Jonathan Kozaczuk , Anthony Aguirre

Two extensions of ideas lying in the basis of the inflationary scenario of the early Universe and their effect on the large scale structure of the present-day Universe are discussed. The first of them is the possibility of fast phase…

Astrophysics · Physics 2007-05-23 A. A. Starobinsky

We study the mixed scalar-tensor two-point function in icosahedral inflation. Within the regime of validity of the effective field theory, this has to be perturbatively small; in particular, much smaller than the scalar spectrum. However,…

High Energy Physics - Theory · Physics 2021-05-05 Alberto Nicolis , Guanhao Sun