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A wide variety of vacua, and their cosmological realization, may provide an explanation for the apparently anthropic choices of some parameters of particle physics and cosmology. If the probability on various parameters is weighted by…

High Energy Physics - Theory · Physics 2008-11-26 Lawrence J. Hall , Taizan Watari , T. T. Yanagida

We consider the measure problem in standard slow-roll inflationary models from the perspective of loop quantum cosmology (LQC). Following recent results by Ashtekar and Sloan, we study the probability of having enough e-foldings and focus…

General Relativity and Quantum Cosmology · Physics 2011-05-12 Alejandro Corichi , Asieh Karami

In this paper, we show that eternal inflation of the random walk type is generically absent in the brane inflationary scenario. Depending on how the brane inflationary universe originated, eternal inflation of the false vacuum type is still…

High Energy Physics - Theory · Physics 2009-11-11 Xingang Chen , Sash Sarangi , S. -H. Henry Tye , Jiajun Xu

Cosmic inflation may exhibit stochastic periods during which quantum fluctuations dominate over the semi-classical evolution. Extracting observables in these regimes is a notoriously difficult program as quantum randomness makes them fully…

Cosmology and Nongalactic Astrophysics · Physics 2025-11-27 Baptiste Blachier , Christophe Ringeval

Extreme Value Theory (EVT) is one of the most commonly used approaches in finance for measuring the downside risk of investment portfolios, especially during financial crises. In this paper, we propose a novel approach based on EVT called…

General Economics · Economics 2020-11-16 Hamidreza Arian , Hossein Poorvasei , Azin Sharifi , Shiva Zamani

We consider the long standing puzzle of how to obtain meaningful probabilities in eternal inflation. We demonstrate a new algorithm to compute the probability distribution of pocket universe types, given a multivacua inflationary potential.…

Astrophysics · Physics 2011-01-20 Richard Easther , Eugene A. Lim , Matthew R. Martin

The global-in-time existence of classical solutions to the relativistic Vlasov-Maxwell (RVM) system in three space dimensions remains elusive after nearly four decades of mathematical research. In this note, a simplified ``toy model'' is…

Analysis of PDEs · Mathematics 2021-12-13 Jonathan Ben-Artzi , Stephen Pankavich , Junyong Zhang

Our universe may be contained in one among a diverging number of bubbles that nucleate within an eternally inflating multiverse. A promising measure to regulate the diverging spacetime volume of such a multiverse is the scale-factor cutoff,…

High Energy Physics - Theory · Physics 2010-05-12 Andrea De Simone , Michael P. Salem

We explore the idea that the dynamics of the inflationary multiverse is encoded in its future boundary, where it is described by a lower dimensional theory which is conformally invariant in the UV. We propose that a measure for the…

High Energy Physics - Theory · Physics 2009-01-16 J. Garriga , A. Vilenkin

We calculate the probability distribution for the volume of the Universe after slow-roll inflation both in the eternal and in the non-eternal regime. Far from the eternal regime the probability distribution for the number of e-foldings,…

High Energy Physics - Theory · Physics 2009-05-01 Sergei Dubovsky , Leonardo Senatore , Giovanni Villadoro

The combined Continuous Time Random Walk (CTRW) in position and momentum space is introduced, in the form of two coupled integral equations that describe the evolution of the probability distribution for finding a particle at a certain…

Chaotic Dynamics · Physics 2007-10-29 H. Isliker

The advancement in the observational cosmology of the early universe such as Cosmic Microwave Background (CMB) observations, puts severe constraints on the inflationary models. Many inflationary models have been ruled out by CMB,…

Cosmology and Nongalactic Astrophysics · Physics 2025-05-20 Yogesh , Mehnaz Zahoor , Kashif Ali Wani , Imtiyaz Ahmad Bhat

We consider the eternal inflation scenario of the slow-roll/chaotic type with the additional element of an objective collapse of the wave function. The incorporation of this new agent to the traditional inflationary setting might represent…

General Relativity and Quantum Cosmology · Physics 2017-10-27 Gabriel Leon

In this paper we shall consider an exponential inflationary model in the context of vacuum $F(R)$ gravity. By using well-known reconstruction techniques, we shall investigate which $F(R)$ gravity can realize the exponential inflation…

General Relativity and Quantum Cosmology · Physics 2018-03-14 V. K. Oikonomou

This paper analyzes the benefits of sampling intraday returns in intrinsic time for the realized variance (RV) estimator. We theoretically show in finite samples that depending on the permitted sampling information, the RV estimator is most…

The $R+R^2$, shortly named "$R^2$" ("Starobinsky") inflationary model, represents a fully consistent example of a one-parameter inflationary scenario. This model has a "graceful exit" from inflation and provides a mechanism for subsequent…

High Energy Physics - Theory · Physics 2016-11-28 Alexey S. Koshelev , Leonardo Modesto , Leslaw Rachwal , Alexei A. Starobinsky

We argue that in the context of eternal inflation in the landscape, making predictions for cosmological -- and possibly particle physics -- observables requires a measure on the possible cosmological histories as opposed to one on the vacua…

High Energy Physics - Theory · Physics 2008-11-26 Anthony Aguirre , Steven Gratton , Matthew C Johnson

There are two main approaches to non-equlibrium statistical mechanics: one using stochastic processes and the other using dynamical systems. To model the dynamics during inflation one usually adopts a stochastic description, which is known…

High Energy Physics - Theory · Physics 2016-03-29 Vitaly Vanchurin

Reheating in inflationary cosmology is essential for understanding the early universe, influencing particle production, thermalization, and the primordial power spectrum. Crucial quantities defined during the reheating epoc, such as the…

Cosmology and Nongalactic Astrophysics · Physics 2025-01-16 Gabriel German

We propose a new measure for eternal inflation, based on search optimization and first-passage statistics. This work builds on the dynamical selection mechanism for vacua based on search optimization proposed recently by the author and…

High Energy Physics - Theory · Physics 2021-06-23 Justin Khoury