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We propose a new approach to Bayesian prior probability distributions (priors) that can improve orbital solutions for low-phase-coverage orbits, where data cover less than approximately 40% of an orbit. In instances of low phase coverage…

Earth and Planetary Astrophysics · Physics 2019-06-12 K. Kosmo O'Neil , G. D. Martinez , A. Hees , A. M. Ghez , T. Do , G. Witzel , Q. Konopacky , E. E. Becklin , D. S. Chu , J. Lu , K. Matthews , S. Sakai

Studies of disordered heterogeneous media and galaxy cosmology share a common goal: analyzing the distribution of particles at `microscales' to predict physical properties at `macroscales', whether for a liquid, composite material, or…

Cosmology and Nongalactic Astrophysics · Physics 2023-01-11 Oliver H. E. Philcox , Salvatore Torquato

We propose a model universe, in which the dimension of the space is a continuous variable, which can take any real positive number. The dynamics leads to a model in which the universe has no singularity. The difference between our model and…

General Relativity and Quantum Cosmology · Physics 2007-05-23 M. Khorrami , R. Mansouri , M. Mohazzab , M. R. Ejtehadi

We describe how difficult it is to realise baryogenesis in models where the fundamental scale in nature is as low as TeV. The problem becomes even more challenging if we assume that there are only {\it two} extra compact spatial dimensions,…

High Energy Physics - Phenomenology · Physics 2007-05-23 Anupam Mazumdar , Rouzbeh Allahverdi , Kari Enqvist , Abdel Pérez-Lorenzana

It has been proposed that the accelerated expansion of the universe can be explained by the merging of our universe with baby universes, resulting in dark energy with a phantom-like equation of state. However, the evidence in favor of it…

Cosmology and Nongalactic Astrophysics · Physics 2025-06-18 Varun Muralidharan , James M. Cline

The formation scenario of the progenitor of iPTF13bvn has been revisited. iPTF13bvn is unique in the sense that a corresponding pre-supernova image has been identified. This has enabled us to strongly constrain the nature of its progenitor.…

High Energy Astrophysical Phenomena · Physics 2017-02-01 Ryosuke Hirai

Flavor violating axion couplings can be in action before recombination, and they can fill the early universe with an additional radiation component. Working within a model-independent framework, we consider an effective field theory for the…

High Energy Physics - Phenomenology · Physics 2022-04-08 Francesco D'Eramo , Seokhoon Yun

The standard model of cosmology relies on the existence of two components, "dark matter" and "dark energy", which dominate the expansion of the Universe. There is no direct proof of their existence, and their nature is still unknown. Many…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 Alexandre Arbey

A model of an emergent universe is obtained in brane world. Here the bulk energy is in the form of cosmological constant, while the brane consists of the Chaplygin gas with the modified equation of state such as $p=A\rho-B/\rho$. Initially…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Asit Banerjee , Tanwi Bandyopadhyay , Subenoy Chakraborty

We study some aspects of cosmologies in 5D models with one infinite extra dimension. Matter is confined to the brane, gravity extends to the bulk. Models with positive and negative tension of the brane are considered. Cosmological evolution…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 Mikhail Z. Iofa

AI models that predict the future behavior of a system (a.k.a. predictive AI models) are central to intelligent decision-making. However, decision-making using predictive AI models often results in suboptimal performance. This is primarily…

Artificial Intelligence · Computer Science 2025-01-13 Akhil S Anand , Shambhuraj Sawant , Dirk Reinhardt , Sebastien Gros

Theoretical investigations into the evolution of the early universe are an essential part of particle physics that allow us to identify viable extensions to the Standard Model as well as motivated parameter space that can be probed by…

Many of the most exciting questions in astrophysics and cosmology, including the majority of observational probes of dark energy, rely on an understanding of the nonlinear regime of structure formation. In order to fully exploit the…

Cosmology and Nongalactic Astrophysics · Physics 2013-05-13 Earl Lawrence , Katrin Heitmann , Martin White , David Higdon , Christian Wagner , Salman Habib , Brian Williams

We study the primordial nucleosynthesis (BBN) in the stepwise scalar field model proposed by Ti\'an [arXiv:1912.13208, Phys. Rev. D 101, 063531 (2020)], which provides a multiaccelerating Universe solution to the cosmological coincidence…

General Relativity and Quantum Cosmology · Physics 2023-02-27 S. X. Tian

The universe may have extra spatial dimensions with large volume that we cannot perceive because the energy required to excite modes in the extra directions is too high. Many examples are known of such manifolds with a large volume and a…

High Energy Physics - Theory · Physics 2011-06-27 Brian Greene , Daniel Kabat , Janna Levin , Dylan Thurston

We construct models of universe with a generalized equation of state $p=(\alpha \rho+k\rho^{1+1/n})c^2$ having a linear component and a polytropic component. In this paper, we consider positive indices $n>0$. In that case, the polytropic…

Cosmology and Nongalactic Astrophysics · Physics 2014-04-07 Pierre-Henri Chavanis

It is very difficult to obtain a realistic model of a closed inflationary universe. Even if one fine-tunes the total number of e-folds to be sufficiently small, the resulting universe typically has large density perturbations on the scale…

Astrophysics · Physics 2009-09-29 Andrei Linde

The beautiful scenario of pre-big-bang cosmology is appealling not only because it is more or less derived from string theory, but also because it separates clearly the problem of the initial conditions for the universe from that of high…

High Energy Physics - Theory · Physics 2007-05-23 M. Borunda , M. Ruiz-Altaba

It appears difficult to construct a simple model for an open universe based on the one bubble inflationary scenario. The reason is that one needs a large mass to avoid the tunneling via the Hawking Moss solution and a small mass for…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Kazuya Koyama , Kayoko Maeda , Jiro Soda

We explore the viability of a bulk viscous matter-dominated Universe to explain the present accelerated expansion of the Universe. The model is composed by a pressureless fluid with bulk viscosity of the form \zeta = \zeta_0 + \zeta_1 * H…

General Relativity and Quantum Cosmology · Physics 2010-10-25 Arturo Avelino , Ulises Nucamendi