Results 131 to 140 of about 550,111 (273)

A new mechanism for freezing extra dimensions with higher-order curvature terms

Physics Letters B, 2020
We construct a model of higher dimensional cosmology in which extra dimensions are frozen by virtue of the cubic-order Lovelock gravity throughout the cosmic history from inflation to the present with radiation and matter-dominated regimes in between.
Hiroaki W.H. Tahara, Tsutomu Kobayashi, Jun'ichi Yokoyama   +2 more
doaj  

Clockwork axions in cosmology. Is chromonatural inflation chrononatural?

Journal of High Energy Physics, 2018
Many cosmological models rely on large couplings of axions to gauge fields. Examples include theories of magnetogenesis, inflation on a steep potential, chiral gravitational waves, and chromonatural inflation. Such theories require a mismatch between the
Prateek Agrawal, JiJi Fan, Matthew Reece
doaj   +1 more source

Eternal inflation and chaotic terminology [PDF]

arXiv, 2004
``Eternal inflation'' is often confused with ``chaotic inflation''. Moreover, the term ``chaotic inflation'' is being used in three different meanings (all of them unrelated to eternal inflation). I make some suggestions in an effort to untangle this terminological mess. I also give a brief review of the origins of eternal inflation.
arxiv  

Auroral Energy Deposition and Conductance During the 2013 St. Patrick's Day Storm: Meso‐Scale Contributions

Journal of Geophysical Research: Space Physics, Volume 130, Issue 2, February 2025.
Abstract Geomagnetic storms transfer massive amounts of energy from the sun to geospace. Some of that energy is dissipated in the ionosphere as energetic particles precipitate and transfer their energy to the atmosphere, creating the aurora. We used the Time History of Events and Macroscale Interactions during Substorms (THEMIS) mosaic of all‐sky ...
Christine Gabrielse, Y. Nishimura, J. H. Hecht, M. W. Chen, S. R. Kaeppler, D. M. Gillies, Y. Deng, E. Spanswick, E. Donovan, J. S. Evans, L. R. Lyons   +10 more
wiley   +1 more source

Inflationary Cosmology in Anisotropic Inflation Models

Iranian Journal of Physics Research, 2018
In this work, we study the anisotropic inflationary models . In these models,  an abelian gauge field  non-minimally coupled to the inflaton field plays a role in the inflation dynamicIn a gauge field,the backgroundanswer is anisotropic, in the
H Firouzjahi, A A Abolhasani
doaj  

Inflation and axion cosmology

Physics Letters B, 1988
Abstract It is argued that the standard constraint ƒ⪷10 12 GeV in the axion theory and related constraints in the theories of other weakly interacting scalar fields do not apply in many versions of the inflationary universe scenario.
Andrei Linde, Andrei Linde
openaire   +2 more sources

Piercing the Martian Veil: A Statistical Study of Interplanetary Magnetic Field Reach Through Ionospheric Pressure Balance

Journal of Geophysical Research: Space Physics, Volume 130, Issue 2, February 2025.
Abstract Mars, being a small planet with a tenuous atmosphere, does not have a sharp boundary between regions dominated by solar wind plasma and planetary plasma. Instead, this transition is typically extended, allowing the interplanetary magnetic field (IMF) to penetrate into the Martian ionosphere.
S. R. Shaver, L. Andersson, R. Ramstad, Bhagyashree Waghule, D. Brain, R. Lillis, T. Cravens, J. Halekas, S. Xu, P. C. Hinton, D. Malaspina, M. W. Liemohn, S. Ledvina, J. R. Gruesbeck, S. Curry   +14 more
wiley   +1 more source

Study of Variation Mechanisms of the Martian Diffuse Aurora Based on Monte Carlo Simulations and MAVEN Observations

Journal of Geophysical Research: Space Physics, Volume 130, Issue 2, February 2025.
Abstract Martian diffuse auroras are ultraviolet emissions spread across the nightside of Mars caused by solar energetic particles (SEP), both electrons and protons. The nightside structures of induced and crustal magnetic fields are expected to affect the diffuse auroral emission profiles caused by electrons, which is far from understood.
Taishin Okiyama, Kanako Seki, Yuki Nakamura, Robert J. Lillis, Ali Rahmati, Davin E. Larson, Gina A. DiBraccio, Nicholas M. Schneider, Sonal K. Jain, Ryoya Sakata, Shannon Curry   +10 more
wiley   +1 more source

Scaling solutions for dilaton quantum gravity

Physics Letters B, 2017
Scaling solutions for the effective action in dilaton quantum gravity are investigated within the functional renormalization group approach. We find numerical solutions that connect ultraviolet and infrared fixed points as the ratio between scalar field ...
T. Henz, J.M. Pawlowski, C. Wetterich
doaj   +1 more source

Statistical Study of Electron Kinetic Entropy Generation at Earth's Quasi‐Perpendicular Bow Shock

Journal of Geophysical Research: Space Physics, Volume 130, Issue 1, January 2025.
Abstract We use the Magnetospheric Multiscale mission to study electron kinetic entropy across Earth's quasi‐perpendicular bow shock. We perform a statistical study of how the change in electron entropy depends on the different plasma parameters associated with a collisionless shock crossing.
M. Lindberg, A. Wallner, S. Berglund, A. Vaivads   +3 more
wiley   +1 more source