scispace - formally typeset
Search or ask a question
Topic

Particle horizon

About: Particle horizon is a research topic. Over the lifetime, 2096 publications have been published within this topic receiving 69137 citations.


Papers
More filters
01 Jan 2007
TL;DR: In this article, the authors use an explicit Randall-Sundrum brane world effective potential as congruent with conditions needed to form a minimum entropy starting point for an early universe vacuum state.
Abstract: We use an explicit Randall-Sundrum brane world effective potential as congruent with conditions needed to form a minimum entropy starting point for an early universe vacuum state. We are investigating if the Jeans instability criteria mandating low entropy, low temperature initial pre inflation state configuration can be reconciled with thermal conditions of temperatures at or above ten to the 12 Kelvin, or higher, when cosmic inflation physics takes over. We justify this by pointing to the Ashtekar, Pawlowski, and Singh (2006) article about a prior universe being modeled via their quantum bounce hypothesis which states that this prior universe geometrically can be modeled via a discretized Wheeler - De Witt equation , with it being the collapsing into a quantum bounce point singularity converse of the present day universe expanding from the quantum bounce point so delineated in their calculations. The prior universe would provide thermal excitation into the Jeans instability mandated cooled down initial state, with low entropy, leading to extreme graviton production. This necessitates reconciling the lack of a quantum bounce seen in brane world models with the proof of relic graviton production so provided in the simulation so provided. This is also a way of getting around the get around the fact that conventional cosmological CMB is limited by a barrier as of a red shift limit of about z = 1000, i.e. when the universe was about 1000 times smaller and 100,000 times younger than today as to photons, and to come up with a working model of quintessence scalar fields which permits relic generation of dark matter/dark energy.

7 citations

Journal ArticleDOI
TL;DR: In this article, the authors study the effect of interacting quintessence DE models in the cosmology with an Effective varying $\Lambda$-Term in Lyra Manifold.
Abstract: We are interested by the study of several toy models of the Universe in presence of interacting quintessence DE models. Models are considered in the cosmology with an Effective varying $\Lambda$-Term in Lyra Manifold. The motivation of the phenomenological models discussed in this paper is to obtain corresponding models to describe and understand an accelerated expansion of the Universe for the later stage of evolution. Phenomenology of the models describes by the phenomenological forms of $\Lambda(t)$ ($8 \pi G =c =1$). Concerning to the mathematical hardness we discuss results numerically and graphically. Obtained results give us hope that proposed models can work as good models for old Universe and in good agreement with observational data.

7 citations

Journal ArticleDOI
TL;DR: In this paper, the authors examined light exchange in fixed spatial coordinates rather than the Robertson-Walker (RW) comoving coordinates both because it provides a graceful transition from special relativity and because it is an interesting exercise by itself.
Abstract: The standard model of light exchange in the expanding universe is usually expressed in the Robertson–Walker (RW) proper distance as a function of RW cosmic time, a standard time which is the same for all points on the expanding spatial coordinates. In these coordinates, light like the cosmic microwave background emitted early in the universe close to the origin recedes before it approaches the earth, taking about one‐third of the universe’s age, t0, to achieve a maximum distance of about ct0/2, traveling outward an average velocity (maximum distance divided by elapsed cosmic time) about 50% greater than c, the normal speed of light in the absence of gravity. This paper examines this light exchange in fixed spatial coordinates rather than the RW comoving coordinates both because it provides a graceful transition from special relativity and because it is an interesting exercise by itself. For this the array of noninertial observers at fixed distances from the origin must have peculiar velocities, moving tow...

7 citations

Journal ArticleDOI
TL;DR: In this paper, the authors investigated the effect of super-inflation in loop quantum cosmology and found that the changes of the scale factor depend on the initial values of energy density of the scalar field and radiation at the bounce point.

7 citations

Journal ArticleDOI
TL;DR: In this paper, it was shown that the observed red shift at the LAB system is due to a real shrinkage of the quantum world, due to the decrease in size of quantum particles determined by a decreasing Planck's "constant".
Abstract: We find five fundamental reasons demanding that any gravitational mass m, and the speed of light c, vary with cosmological time such that mc remains constant. This is required by the universal condition of conservation of momentum in a Universe with spatial homogeneity. We prove that this is consistent with Einstein's Theory of General Relativity. We call this effect a "MASS BOOM". At the LAB system no such time variations can be detected, unless we make comparisons with cosmological observations. We have to stress that the physical conditions implied by a time varying mass, together with a time varying speed of light, preserving the constancy of momentum, are compatible with Einstein's field equations. We then integrate his cosmological equations and find the solution for the cosmological scale factor a(t) proportional to the square of time, implying an apparent accelerated expansion for the Universe, as seen from the LAB frame. This is the interpretation given to recent observations obtained from the Supernova Type Ia. This determination of the scale factor a(t) is based upon a LAB interpretation and therefore is an apparent effect. On the other hand we note that the product ct being a constant determines the real Universe as a static one, of constant size. The observed red shift at the LAB system is due to a real shrinkage of the quantum world, due to the decrease in size of the quantum particles determined by a decreasing Planck's "constant".

7 citations


Network Information
Related Topics (5)
Black hole
40.9K papers, 1.5M citations
88% related
Dark matter
41.5K papers, 1.5M citations
86% related
Gauge theory
38.7K papers, 1.2M citations
85% related
Neutrino
45.9K papers, 1M citations
84% related
Supersymmetry
29.7K papers, 1.1M citations
83% related
Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202320
202247
20216
202010
201910
201814