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We compute the fluctuations of the magnetization and of the multi-overlaps for the dilute mean field ferromagnet, in the high temperature region. The rescaled magnetization tends to a centered Gaussian variable with variance diverging at…

Mathematical Physics · Physics 2008-11-14 Luca De Sanctis

We investigate non-Gaussianity in general multiple-field inflation using the formalism we developed in earlier papers. We use a perturbative expansion of the non-linear equations to calculate the three-point correlator of the curvature…

Astrophysics · Physics 2009-11-13 G. I. Rigopoulos , E. P. S. Shellard , B. J. W. van Tent

We study the fluctuations in the vacuum zero point energy associated to quantum fields and their statistical distributions during inflation. It is shown that the perturbations in the vacuum zero point energy have large amplitudes which are…

Cosmology and Nongalactic Astrophysics · Physics 2025-05-20 Hassan Firouzjahi

Enhancements of primordial curvature fluctuations in single field inflation often involve departures from attractor trajectories in the phase space. We study enhancement/suppression of primordial fluctuations in one of the simplest models…

Cosmology and Nongalactic Astrophysics · Physics 2023-09-25 Guillem Domènech , Gerson Vargas , Teófilo Vargas

The dimer model on a planar bipartite graph can be viewed as a random surface measure. We study these fluctuations for a dimer model on the square grid with two different classes of weights and provide a condition for their equivalence. In…

Probability · Mathematics 2015-05-27 Sunil Chhita

Across a large range of scales, accreting sources show remarkably similar patterns of variability, most notably the log-normality of the luminosity distribution and the linear root-mean square (rms)-flux relationship. These results are…

High Energy Astrophysical Phenomena · Physics 2024-01-30 Samuel G. D. Turner , Christopher S. Reynolds

We investigate the large deviation function pi(w) for the fluctuations of the power W(t)=w t, integrated over a time t, injected by a homogeneous random driving into a granular gas, in the infinite time limit. Starting from a generalized…

Statistical Mechanics · Physics 2007-05-23 P. Visco , A. Puglisi , A. Barrat , E. Trizac , F. van Wijland

We review the basic arguments for the likelihood of non-Gaussian density perturbations in inflation models with primordial black hole (PBH) production. We discuss our derived distributions of field fluctuations and their implications,…

Astrophysics · Physics 2007-05-23 James S. Bullock , Joel R. Primack

It was shown by Garriga and Vilenkin that the circular shape of nucleated cosmic strings, of zero loop-energy in de Sitter space, is stable in the sense that the ratio of the mean fluctuation amplitude to the loop radius is constant. This…

High Energy Physics - Theory · Physics 2009-10-28 A. L. Larsen

Experimental and theoretical studies are made of Brownian particles trapped in a periodic potential, which is very slightly tilted due to gravity. In the presence of fluctuations, these will trigger a measurable average drift along the…

Atomic Physics · Physics 2010-10-14 M. Zelan , H. Hagman , K. Karlsson , C. M. Dion , A. Kastberg

Calculating the action and the interaction Hamiltonian at higher orders in cosmological perturbation theory is a cumbersome task. We employ the formalism of EFT of inflation in the decoupling limit for single-field ultra slow-roll (USR)…

Cosmology and Nongalactic Astrophysics · Physics 2026-05-15 Hassan Firouzjahi , Bahar Nikbakht

We present a class of models in which the primordial metric fluctuations do not necessarily obey Gaussian statistics. These models are realizations of mechanisms in which non-Gaussianity is first generated by a light scalar field and then…

Astrophysics · Physics 2009-11-11 Francis Bernardeau , Tristan Brunier , Jean-Philippe Uzan

A spectator axion-gauge sector, minimally coupled to the inflaton, with the axion experiencing a momentary stage of fast roll during cosmological inflation, can generate unique signatures in primordial density fluctuations and the…

Cosmology and Nongalactic Astrophysics · Physics 2025-01-28 Angelo Caravano , Marco Peloso

Finite size fluctuations are a crucial ingredient in kinetic theory of long-range interacting collisionless systems. In this Letter, we introduce a phenomenological theory which predicts an anomalous scaling close to marginal stability for…

Statistical Mechanics · Physics 2026-03-19 Yoshiyuki Y. Yamaguchi , Julien Barré

We estimate fermion loop corrections to the two-point correlation function of primordial tensor perturbations in a slow-roll inflationary background. We particularly compute an explicit term of one-loop correction from a massless fermion,…

High Energy Physics - Theory · Physics 2012-11-22 Kaixi Feng , Yi-Fu Cai , Yun-Song Piao

We study a general class of log-gas ensembles on (shifted) quadratic lattices. We prove that the corresponding empirical measures satisfy a law of large numbers and that their global fluctuations are Gaussian with a universal covariance. We…

Probability · Mathematics 2018-05-01 Evgeni Dimitrov , Alisa Knizel

We develop a non-perturbative formalism for scalar metric fluctuations from a 5D extended version of general relativity in vacuum. In this work we concentrate our efforts on calculations valid on large cosmological scales, which are the…

General Relativity and Quantum Cosmology · Physics 2015-06-15 José Edgar Madriz Aguilar , Luz Marina Reyes , Claudia Moreno , Mauricio Bellini

Canonical models of single-field, slow-roll inflation do not lead to appreciable non-Gaussianity, unless derivative interactions of the inflaton become uncontrollably large. We propose a novel slow-roll scenario where scalar perturbations…

High Energy Physics - Theory · Physics 2016-05-25 David Pirtskhalava , Luca Santoni , Enrico Trincherini , Filippo Vernizzi

We study stationary fluctuations at criticality for a one-dimensional reaction--diffusion process combining symmetric simple exclusion dynamics with Glauber-type spin flips. The strength of the Glauber interaction is tuned to the critical…

Probability · Mathematics 2026-03-11 Luis Cardoso , Claudio Landim , Kenkichi Tsunoda

The dynamics of a one-dimensional stochastic model is studied in presence of an absorbing boundary. The distribution of fluctuations is analytically characterized within the generalized van Kampen expansion, accounting for higher order…

Statistical Mechanics · Physics 2015-05-28 Claudia Cianci , Francesca Di Patti , Duccio Fanelli