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200 papers

We perform microscopic simulations of the thermal relaxation of warm neutral plasmas of astrophysical importance. Using Molecular Dynamics we study the thermal relaxation of a hot neutral fluid of finite-size neutron-rich ions kept in a…

Plasma Physics · Physics 2025-08-05 David Barba-González , Conrado Albertus , M. Ángeles Pérez-García

In curvaton-type models, observable non-gaussianity of the curvature perturbation would come from a contribution of the form $(\delta\sigma)^2$, where $\delta\sigma$ is gaussian. I analyse this situation allowing $\delta\sigma$ to be…

Astrophysics · Physics 2009-11-11 D. H. Lyth

The curvature drift instability has long been considered as a viable mechanism for pulsar radio emission. We reconsidered this mechanism by finding an explicit solution describing propagation of short-wave electro-magnetic waves in a plasma…

High Energy Astrophysical Phenomena · Physics 2015-05-19 Alexander Kaganovich , Yuri Lyubarsky

In order to describe properties of an equilibrated quark-gluon plasma, QCD at finite temperature (and density) has to be considered. Besides lattice calculations, which can be applied only to static quantities at zero density, perturbative…

High Energy Physics - Phenomenology · Physics 2009-10-31 Markus H. Thoma

We obtain self-similar solutions that describe the dynamics of a self-gravitating, rotating, viscous system. We use simplifying assumptions; but explicitly include viscosity and the cooling due to the dissipation of energy. By assuming that…

Astrophysics · Physics 2009-11-07 Mohsen Shadmehri , Jamshid Ghanbari

The spatial curvature of the universe is not yet known. Even though at present the Universe is very close to being essentially flat and most signatures of curvature appear to have been diluted by inflation, if the number of e-foldings…

High Energy Physics - Theory · Physics 2021-12-23 Sebastian Cespedes , Senarath de Alwis , Francesco Muia , Fernando Quevedo

We consider models of inflation that contain a transient non-slow-roll stage and investigate the conditions under which a dip appears in the power spectrum of the curvature perturbation. Using the $\delta N$ formalism, we derive a general…

Cosmology and Nongalactic Astrophysics · Physics 2025-09-19 Tomohiro Fujita , Ryodai Kawaguchi , Misao Sasaki , Yuichiro Tada

The modeling of turbulence, whether it be numerical or analytical, is a difficult challenge. Turbulence is amenable to analysis with linear theory if it is subject to rapid distortions, i.e., motions occurring on a time scale that is short…

High Energy Astrophysical Phenomena · Physics 2015-06-19 Bryan M. Johnson

This study explores the impact of cosmic curvature on structure formation through general relativistic first-order perturbation theory. We analyze continuity and Euler equations, incorporating cosmic curvature into Einstein equations.…

Cosmology and Nongalactic Astrophysics · Physics 2025-05-29 Bikash R. Dinda

We comprehensively explore the quadratic curvaton models in the chaotic inflation. In the light of the BICEP2 result $r \approx 0.2$, all model parameters and relevant observables are computed. It is found the curvaton field value is…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-19 Tomohiro Fujita , Masahiro Kawasaki , Shuichiro Yokoyama

In this article we discuss the effect of curvature on dynamics when a physical system moves adiabatically in a curved space. These effects give a way to measure the curvature of the space intrinsically without referring to higher…

General Physics · Physics 2015-03-17 Gautam Dutta

We investigate non-Gaussianity in the modulated reheating scenario where fluctuations of the decay rate of the inflaton generate adiabatic perturbations, paying particular attention to the non-linearity parameters $f_{\rm NL}, \tau_{\rm…

Astrophysics · Physics 2008-11-26 Kazuhide Ichikawa , Teruaki Suyama , Tomo Takahashi , Masahide Yamaguchi

The kinetic energy of bulk relativistic plasma ejected from the central engine of blazars is converted into nonthermal particle energy in the comoving frame through a process of sweeping up material from the surrounding medium. The…

Astrophysics · Physics 2009-10-31 Charles D. Dermer

We investigate the creation of dark matter particles as a result of the decay of the scalar field in the framework of warm inflationary models, by using the irreversible thermodynamics of open systems with matter creation/annihilation. We…

General Relativity and Quantum Cosmology · Physics 2023-03-07 Teodora Matei , Tiberiu Harko , Gabriela Mocanu

Compressible turbulence governs energy transfer across scales in space and astrophysical systems. Capturing both the turbulence cascade and damping is therefore crucial for models of energy conversion, plasma heating, and particle transport…

Solar and Stellar Astrophysics · Physics 2025-09-30 Chuanpeng Hou , Huirong Yan , Siqi Zhao , Parth Pavaskar

Curvature plays a central role in the proper function of many biological processes. With active matter being a standard framework for understanding many aspects of the physics of life, it is natural to ask what effect curvature has on the…

Soft Condensed Matter · Physics 2026-01-27 Euan D. Mackay , Giulia Janzen , D. A. Matoz Fernandez , Rastko Sknepnek

We discuss the onset of the thermalization process in high-energy heavy-ion collisions from a weak coupling perspective, using classical-statistical real-time lattice simulations as a first principles tool to study the pre-equilibrium…

High Energy Physics - Phenomenology · Physics 2014-09-08 Jürgen Berges , Björn Schenke , Sören Schlichting , Raju Venugopalan

In this paper we consider how non-Gaussianity of the primordial density perturbation and the amplitude of gravitational waves from inflation can be used to determine parameters of the curvaton scenario for the origin of structure. We show…

Cosmology and Nongalactic Astrophysics · Physics 2011-03-22 José Fonseca , David Wands

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

The expected tensor-to-scalar ratio estimate of the upcoming CMB mission probe measurements may establish a lower value of the ratio than the currently obtained value. It can be described in terms of a single field chaotic inflation model…

General Relativity and Quantum Cosmology · Physics 2021-09-28 P K Suresh
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