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The simplicity of the CMB data, so well described by single-field inflation, raises the question whether there might be an equally simple multi-field realization consistent with the observations. We explore the idea that an approximate…

High Energy Physics - Theory · Physics 2019-07-04 Ana Achucarro , Yvette Welling

We develop a non-linear framework for describing long-wavelength perturbations in multiple-field inflation. The basic variables describing inhomogeneities are defined in a non-perturbative manner, are invariant under changes of time slicing…

Astrophysics · Physics 2009-11-11 G. I. Rigopoulos , E. P. S. Shellard , B. J. W. van Tent

We discuss the possible role of isocurvature perturbations for the quantum decoherence of the curvature perturbation during inflation. We point out that if the inflaton trajectory in field space is curved, the adiabatic mode is generically…

Astrophysics · Physics 2011-08-04 Tomislav Prokopec , Gerasimos I. Rigopoulos

We analyze and compare the multi-field dynamics during inflation and preheating in symmetric and asymmetric models of $\alpha$-attractors, characterized by a hyperbolic field-space manifold. We show that the generalized (asymmetric) E- and…

Cosmology and Nongalactic Astrophysics · Physics 2020-05-04 Oksana Iarygina , Evangelos I. Sfakianakis , Dong-Gang Wang , Ana Achúcarro

We describe models of single-field inflation with small and sharp step features in the potential (and sound speed) of the inflaton field, in the context of the Effective Field Theory of Inflation. This approach allows us to study the…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-16 Nicola Bartolo , Dario Cannone , Sabino Matarrese

In this paper we study output coding for multi-label prediction. For a multi-label output coding to be discriminative, it is important that codewords for different label vectors are significantly different from each other. In the meantime,…

Machine Learning · Computer Science 2012-07-03 Yi Zhang , Jeff Schneider

Inflation is a highly favoured theory for the early Universe. It is compatible with current observations of the cosmic microwave background and large scale structure and is a driver in the quest to detect primordial gravitational waves. It…

Cosmology and Nongalactic Astrophysics · Physics 2024-04-19 Tomás Sousa , Deaglan J. Bartlett , Harry Desmond , Pedro G. Ferreira

We present a Fortran 77/95 code capable of computing QCD corrections in deep inelastic scattering (DIS). The code uses the Projection-to-Born method to augment an existing $\mathcal{O}(\alpha_s^2)$ dijet DIS code, thereby obtaining…

High Energy Physics - Phenomenology · Physics 2024-07-31 Alexander Karlberg

We develop a covariant method for studying the effects of a reheating phase on the primordial adiabatic and isocurvature perturbations in two-field models of inflation. To model the decay of the scalar fields into radiation at the end of…

High Energy Physics - Theory · Physics 2018-12-12 Pablo González , Gonzalo A. Palma , Nelson Videla

We develop the path integral formalism for studying cosmological perturbations in multi-field inflation, which is particularly well suited to study quantum theories with gauge symmetries such as diffeomorphism invariance. We formulate the…

High Energy Physics - Theory · Physics 2016-08-24 Jinn-Ouk Gong , Min-Seok Seo , Gary Shiu

The scalar perturbations in inflationary models, based on a two-component diagonal non-linear sigma model, are considered. For inhomogeneities generated at an inflationary stage, the law of motion of the comoving curvature ${\cal R}$ is…

Astrophysics · Physics 2007-05-23 N. A. Koshelev

Forthcoming missions probing the absolute intensity of the CMB are expected to be able to measure spectral distortions, which are deviations from its blackbody distribution. As cosmic inflation can induce spectral distortions, these…

Cosmology and Nongalactic Astrophysics · Physics 2024-04-22 Alexander Baur , Marcos A. G. Garcia , Raul Henriquez-Ortiz , Mauricio Hernandez-Neri , Saul Ramos-Sanchez

In the present paper, we study the non-Gaussianity of multiple-field inflation model using the method of the field equation. We start from reviewing the background and the perturbation theory of multiple-field inflation, and then derive the…

Astrophysics · Physics 2008-04-04 Shi-Wen Li , Wei Xue

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

In this work we detail the application of a fast convolution algorithm computing high dimensional integrals to the context of multiplicative noise stochastic processes. The algorithm provides a numerical solution to the problem of…

Computational Finance · Quantitative Finance 2015-03-19 Giacomo Bormetti , Sofia Cazzaniga

Stochastic inflation, together with the $\Delta N$ formalism, provides a powerful tool for estimating the large-scale behaviour of primordial fluctuations. In this work, we develop a numerical code to capture the non-perturbative statistics…

Cosmology and Nongalactic Astrophysics · Physics 2025-03-10 Devanshu Sharma

Utilizing the Maldacena formalism and extending the earlier efforts to compute the scalar bi-spectrum, we construct a numerical procedure to evaluate the three-point scalar-tensor cross-correlations as well as the tensor bi-spectrum in…

Cosmology and Nongalactic Astrophysics · Physics 2013-12-17 V. Sreenath , Rakesh Tibrewala , L. Sriramkumar

We investigate the consequences of general curved trajectories in multi-field inflation. After setting up a completely general formalism using the mass basis, which naturally accommodates the notion of light and heavy modes, we study in…

Cosmology and Nongalactic Astrophysics · Physics 2015-09-30 Xian Gao , Jinn-Ouk Gong

In this work, we construct an explicit string motivated example of three-field inflation in a related, yet distinct from, the recently discovered perturbative large volume scenario (pLVS). Contrary to the usual constructions, in this set…

High Energy Physics - Theory · Physics 2025-02-25 Vasileios Basiouris , Dibya Chakraborty

We explore preheating in multi-field models of inflation in which the field-space metric is a highly curved hyperbolic manifold. One broad family of such models is called $\alpha$-attractors, whose single-field regimes have been extensively…

Cosmology and Nongalactic Astrophysics · Physics 2019-06-17 Oksana Iarygina , Evangelos I. Sfakianakis , Dong-Gang Wang , Ana Achucarro