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We derive oscillatory signals in correlation functions in two-field open inflation by means of the in-in formalism; such signatures are caused by resonances between oscillations in the tunnelling field and fluctuations in the inflaton…

Cosmology and Nongalactic Astrophysics · Physics 2013-05-14 Thorsten Battefeld , Jens C. Niemeyer , Dimitar Vlaykov

Tensor non-Gaussianity represents an important future probe of the physics of inflation. Inspired by recent works, we elaborate further on the possibility of significant primordial tensor non-Gaussianities sourced by extra fields during…

Cosmology and Nongalactic Astrophysics · Physics 2019-02-20 Emanuela Dimastrogiovanni , Matteo Fasiello , Gianmassimo Tasinato , David Wands

We study a 2-parametric family of probability measures on an infinite-dimensional simplex (the Thoma simplex). These measures originate in harmonic analysis on the infinite symmetric group (S.Kerov, G.Olshanski and A.Vershik, Comptes Rendus…

Representation Theory · Mathematics 2008-03-02 Grigori Olshanski

Sudden violations of the slow-roll regime during inflation, a natural prediction of many UV-complete inflationary models, give rise to sharp features in the primordial power spectrum. At large scales, these features provide a unique window…

Cosmology and Nongalactic Astrophysics · Physics 2025-02-05 Clément Stahl , Denis Werth , Vivian Poulin

This paper considers warm inflation as an interesting application of multi-field inflation. Delta-N formalism is used for the calculation of the evolution of the curvature perturbations during warm inflation. Although the perturbations…

Cosmology and Nongalactic Astrophysics · Physics 2010-04-28 Tomohiro Matsuda

We derive the first terms in the amplitude of lepton pair production in the Coulomb fields of two relativistic heavy ions. Using the Sudakov technique, which very simplify the calculations in momentum space for the processes at high…

High Energy Physics - Phenomenology · Physics 2016-09-06 E. Bartos , S. R. Gevorkyan , E. A. Kuraev , N. N. Nikolaev

We show how importance sampling can be used to reconstruct the statistics of rare cosmological fluctuations in stochastic inflation. We have developed a publicly available package, PyFPT, that solves the first-passage time problem of…

Cosmology and Nongalactic Astrophysics · Physics 2022-10-27 Joseph H. P. Jackson , Hooshyar Assadullahi , Kazuya Koyama , Vincent Vennin , David Wands

We aim at capturing high-order statistics of feature vectors formed by a neural network, and propose end-to-end second- and higher-order pooling to form a tensor descriptor. Tensor descriptors require a robust similarity measure due to low…

Computer Vision and Pattern Recognition · Computer Science 2023-12-19 Lei Wang , Ke Sun , Piotr Koniusz

The self-energy of the critical 3-dimensional O(N) model is calculated. The analysis is performed in the context of the Non-Perturbative Renormalization Group, by exploiting an approximation which takes into account contributions of an…

Statistical Mechanics · Physics 2008-11-26 Federico Benitez , Ramon Mendez Galain , Nicolas Wschebor

We study the non-Gaussianity and secondary Gravitational Waves (GWs) in the process of the Primordial Black Holes (PBHs) production from inflation. In our work, we focus on the $\alpha$-attractor inflation model in which a tiny bump in the…

General Relativity and Quantum Cosmology · Physics 2022-08-31 Kazem Rezazadeh , Zeinab Teimoori , Saeid Karimi , Kayoomars Karami

Using perturbation theory, we explore the universal high momentum behavior of correlation functions of gauge invariant operators in planar noncommutative gauge theories. We find that the correlation functions are strongly enhanced when…

High Energy Physics - Theory · Physics 2009-10-31 Moshe Rozali , Mark Van Raamsdonk

We analyze a distinctive mechanism for inflation in which particle production slows down a scalar field on a steep potential, and show how it descends from angular moduli in string compactifications. The analysis of density perturbations --…

High Energy Physics - Theory · Physics 2009-11-06 Daniel Green , Bart Horn , Leonardo Senatore , Eva Silverstein

Hybrid inflation models are especially interesting as they lead to a spike in the density power spectrum on small scales, compared to the CMB, while also satisfying current bounds on tensor modes. Here we study hybrid inflation with $N$…

Cosmology and Nongalactic Astrophysics · Physics 2015-07-28 Illan F. Halpern , Mark P. Hertzberg , Matthew A. Joss , Evangelos I. Sfakianakis

We investigate the gravitational production of a scalar field $\chi$ with a mass exceeding the Hubble scale during inflation $m_\chi \gtrsim H_I$, employing both analytical and numerical approaches. We demonstrate that the steepest descent…

High Energy Physics - Phenomenology · Physics 2024-05-24 Davide Racco , Sarunas Verner , Wei Xue

We present a new algorithm for efficiently computing the $N$-point correlation functions (NPCFs) of a 3D density field for arbitrary $N$. This can be applied both to a discrete spectroscopic galaxy survey and a continuous field. By…

Instrumentation and Methods for Astrophysics · Physics 2021-10-27 Oliver H. E. Philcox , Zachary Slepian , Jiamin Hou , Craig Warner , Robert N. Cahn , Daniel J. Eisenstein

We present Feynman type diagrams for calculating the n-point function of the primordial curvature perturbation in terms of scalar field perturbations during inflation. The diagrams can be used to evaluate the corresponding terms in the…

High Energy Physics - Theory · Physics 2009-10-09 Christian T. Byrnes , Kazuya Koyama , Misao Sasaki , David Wands

A generic prediction of the Coleman-Weinberg inflation is the existence of a heavy particle sector whose interactions with the inflaton, the lightest state in this sector, generate the inflaton potential at loop level. For typical…

High Energy Physics - Phenomenology · Physics 2017-03-20 Kristjan Kannike , Antonio Racioppi , Martti Raidal

Thanks to technological advances leading to near-continuous time observations, emerging multivariate point process data offer new opportunities for causal discovery. However, a key obstacle in achieving this goal is that many relevant…

Machine Learning · Statistics 2021-12-15 Xu Wang , Ali Shojaie

We describe a set of new estimators for the N-point correlation functions of point processes. The variance of these estimators is calculated for the Poisson and binomial cases. It is shown that the variance of the unbiased estimator…

Astrophysics · Physics 2007-05-23 Istvan Szapudi , Alexander S. Szalay

Point processes are becoming very popular in modeling asynchronous sequential data due to their sound mathematical foundation and strength in modeling a variety of real-world phenomena. Currently, they are often characterized via intensity…

Machine Learning · Computer Science 2017-05-24 Shuai Xiao , Mehrdad Farajtabar , Xiaojing Ye , Junchi Yan , Le Song , Hongyuan Zha