scholarly journals Cosmology and Matter-Induced Branes

Symmetry ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 45 ◽  
Author(s):  
Sergey G. Rubin
Keyword(s):  
Significant Role ◽  
Cosmological Parameters ◽  
Fine Tuning ◽  
Matter Distribution ◽  
Hierarchy Problem ◽  
Planck Mass ◽  
Extra Space ◽  
Modern Physics ◽  
Cosmological Constants

The extra space paradigm plays a significant role in modern physics and cosmology as a specific case. In this review, the relation between the main cosmological parameters—the Planck mass and the Cosmological constants—and a metric of extra space is discussed. Matter distribution inside extra space and its effect on the 4-dimensional observational parameters is of particular interest. The ways to solve the fine-tuning problem and the hierarchy problem are analyzed.

God and the Uniformity of Nature

2019 ◽  
pp. 97-110
Author(s):  
Matthew Stanley
Keyword(s):  
Natural World ◽  
Fine Tuning ◽  
Late Nineteenth Century ◽  
James Clerk Maxwell ◽  
Modern Physics ◽  
William Thomson ◽  
Alternative Approaches ◽  
Religiously Based ◽  
John Tyndall ◽  
Lord Kelvin

Today the laws of physics are often seen as evidence for a naturalistic worldview. However, historically, physics was usually considered compatible with belief in God. Foundations of physics such as thermodynamics, uniformity of nature, and causality were seen as religiously based by physicists such as James Clerk Maxwell and William Thomson, Lord Kelvin. These were usually interpreted as evidence of design by a creative deity. In the late nineteenth century, John Tyndall and other scientific naturalists made the argument that these foundations were more sympathetic to a non-religious understanding of the natural world. With the success of this approach, twentieth-century religious physicists tended to stress non-material and experiential connections rather than looking for evidence of design. Later parts of that century saw a revival of natural theological arguments in the form of the anthropic principle and the fine-tuning problem. While modern physics is naturalistic, this was not inevitable and there were several alternative approaches common in earlier times.

scholarly journals Exploring the dark universe: Constraints on dynamical dark energy models from CMB, BAO and growth rate measurements

2019 ◽  
Vol 28 (09) ◽  
pp. 1950118 ◽  
Author(s):  
Alexander Bonilla Rivera ◽  
Jorge Enrique García-Farieta
Keyword(s):  
Dark Energy ◽  
Observational Data ◽  
Cosmological Parameters ◽  
Growth Parameter ◽  
Information Criteria ◽  
Fine Tuning ◽  
Coincidence Problem ◽  
Shift Parameter ◽  
History Of ◽  
Dynamical Dark Energy

In order to explain the current acceleration of the universe, the fine-tuning problem of the cosmological constant [Formula: see text] and the cosmic coincidence problem, different alternative models have been proposed in the literature. We use the most recent observational data from CMB (Planck 2018 final data release) and LSS (SDSS, WiggleZ, VIPERS) to constrain dynamical dark energy (DE) models. The CMB shift parameter, which traditionally has been used to determine the main cosmological parameters of the standard model [Formula: see text], is employed in addition to data from redshift-space distortions through the growth parameter [Formula: see text] to constrain the mass variance [Formula: see text]. BAO data are also used to study the history of the cosmological expansion and the main properties of DE. From the evolution of [Formula: see text], we found a slowdown of acceleration behavior at low redshifts, and by using the Akaike and Bayesian Information Criteria (AIC, BIC), we discriminate different models to find those that are better suited to the observational data, finding that the interacting dark energy (IDE) model is the most favored by observational data, including information from SNIa and Hz. The analysis shows that the IDE model is followed closely by EDE and [Formula: see text] models, which in some cases fit better the observational data with individual probes.

scholarly journals Inflationary limits on the size of compact extra space

2019 ◽  
Vol 28 (13) ◽  
pp. 1941004 ◽  
Author(s):  
V. V. Nikulin ◽  
Sergey G. Rubin
Keyword(s):  
Scalar Field ◽  
Planck Mass ◽  
Extra Space ◽  
Inflationary Models ◽  
Kaluza Klein

We study restrictions imposed on the parameters of the Kaluza–Klein extra space supplied by the standard inflationary models. It is shown that the size of the extra space cannot be larger than [Formula: see text][Formula: see text]cm and the [Formula: see text]-dimensional Planck mass should be larger than [Formula: see text][Formula: see text]GeV. The validity of these estimates is discussed. We also study creation of stable excitations of scalar field as the result of the extra metric evolution.

scholarly journals NONUNIVERSAL GAUGINO MASSES AND NATURAL SUPERSYMMETRY

2013 ◽  
Vol 28 (13) ◽  
pp. 1350046 ◽  
Author(s):  
ILIA GOGOLADZE ◽  
FARIHA NASIR ◽  
QAISAR SHAFI
Keyword(s):  
Standard Model ◽  
Quark Mass ◽  
Higgs Mass ◽  
Mass Range ◽  
Fine Tuning ◽  
Hierarchy Problem ◽  
Light Stop ◽  
High Scale ◽  
Little Hierarchy Problem ◽  
Gaugino Masses

We demonstrate that natural supersymmetry is readily realized in the framework of SU(4)c×SU(2)L×SU(2)Rwith nonuniversal gaugino masses. Focusing on ameliorating the little hierarchy problem, we explore the parameter space of this model which yields small fine-tuning measuring parameters (natural supersymmetry) at the electroweak scale (ΔEW) as well as at high scale (ΔHS). It is possible to have both ΔEWand ΔHSless than 100 in these models, (2% or better fine-tuning), while keeping the light CP-even (Standard Model-like) Higgs mass in the 123–127 GeV range. The light stop quark mass lies in the range [Formula: see text], and the range for the light stau lepton mass is [Formula: see text]. The first two family squarks are in the mass range [Formula: see text], and for the gluino we find [Formula: see text]. We do not find any solution with natural supersymmetry which yields significant enhancement for Higgs production and decay in the diphoton channel.

scholarly journals Combining Probes

2014 ◽  
Vol 10 (S306) ◽  
pp. 192-201
Author(s):  
Anaïs Rassat ◽  
François Lanusse ◽  
Donnacha Kirk ◽  
Ole Host ◽  
Sarah Bridle
Keyword(s):  
Dark Matter ◽  
Cosmological Parameters ◽  
Fundamental Aspect ◽  
Wide Field ◽  
Matter Distribution ◽  
Microwave Background ◽  
Field Surveys ◽  
Galaxy Surveys ◽  
Dark Matter Distribution ◽  
Combining Information

AbstractWith the advent of wide-field surveys, cosmology has entered a new golden age of data where our cosmological model and the nature of dark universe will be tested with unprecedented accuracy, so that we can strive for high precision cosmology. Observational probes like weak lensing, galaxy surveys and the cosmic microwave background as well as other observations will all contribute to these advances. These different probes trace the underlying expansion history and growth of structure in complementary ways and can be combined in order to extract cosmological parameters as best as possible. With future wide-field surveys, observational overlap means these will trace the same physical underlying dark matter distribution, and extra care must be taken when combining information from different probes. Consideration of probe combination is a fundamental aspect of cosmostatistics and important to ensure optimal use of future wide-field surveys.

scholarly journals TwInflation

2021 ◽  
Vol 2021 (7) ◽  
Author(s):  
Kaustubh Deshpande ◽  
Soubhik Kumar ◽  
Raman Sundrum
Keyword(s):  
General Structure ◽  
Ultra Violet ◽  
Effective Field ◽  
Fine Tuning ◽  
Hierarchy Problem ◽  
Future Directions ◽  
Cosmic Inflation ◽  
Hybrid Mechanism ◽  
The Face ◽  
Hybrid Inflation

Abstract The general structure of Hybrid Inflation remains a very well-motivated mechanism for lower-scale cosmic inflation in the face of improving constraints on the tensor-to-scalar ratio. However, as originally modeled, the “waterfall” field in this mechanism gives rise to a hierarchy problem (η−problem) for the inflaton after demanding standard effective field theory (EFT) control. We modify the hybrid mechanism and incorporate a discrete “twin” symmetry, thereby yielding a viable, natural and EFT-controlled model of non-supersymmetric low-scale inflation, “Twinflation”. Analogously to Twin Higgs models, the discrete exchange-symmetry with a “twin” sector reduces quadratic sensitivity in the inflationary potential to ultra-violet physics, at the root of the hierarchy problem. The observed phase of inflation takes place on a hilltop-like potential but without fine-tuning of the initial inflaton position in field-space. We also show that all parameters of the model can take natural values, below any associated EFT-cutoff mass scales and field values, thus ensuring straightforward theoretical control. We discuss the basic phenomenological considerations and constraints, as well as possible future directions.

scholarly journals The flatness problem and the age of the Universe

2020 ◽  
Vol 495 (4) ◽  
pp. 3571-3575
Author(s):  
Phillip Helbig
Keyword(s):  
Early Universe ◽  
Time Scale ◽  
Cosmological Parameters ◽  
Hubble Constant ◽  
Fine Tuning ◽  
Density Parameter ◽  
Age Of The Universe ◽  
Short Time ◽  
The Universe ◽  
Flatness Problem

ABSTRACT Several authors have made claims, none of which has been rebutted, that the flatness problem, as formulated by Dicke and Peebles, is not really a problem but rather a misunderstanding. Nevertheless, the flatness problem is still widely perceived to be real. Most of the arguments against the idea of a flatness problem are based on the change with time of the density parameter Ω and normalized cosmological constant λ and, since the Hubble constant H is not considered, are independent of time-scale. An independent claim is that fine-tuning is required in order to produce a Universe which neither collapsed after a short time nor expanded so quickly that no structure formation could take place. I show that this claim does not imply that fine-tuning of the basic cosmological parameters is necessary, in part for similar reasons as in the more restricted flatness problem and in part due to an incorrect application of the idea of perturbing the early Universe in a gedankenexperiment; I discuss some typical pitfalls of the latter.

Anthropic Contingency

2020 ◽  
pp. 185-197
Author(s):  
Alastair Wilson
Keyword(s):  
Quantum Mechanics ◽  
Quantum Theory ◽  
Cosmological Parameters ◽  
Selection Effect ◽  
Fine Tuning ◽  
Interpretation Of Quantum Mechanics ◽  
Correct Interpretation ◽  
The One ◽  
Observation Selection

Distinguish contingency in general from anthropic contingency. The former is what really could happen; the latter is what really could be observed to happen. Quantum histories which host no life cannot, as a matter of obvious necessity, be observed. This distinction generates an anthropic observation selection effect, which has been employed in response to the fine-tuning argument for the design hypothesis. This chapter argues that fine-tuning is a genuine phenomenon that cries out for explanation; that in one-world approaches to quantum theory a chancy determination of cosmological parameters would render the one universe we are in preposterously lucky; that no preposterous luck is required from the perspective of quantum modal realism; and that the correct interpretation of quantum mechanics turns out to have a significant evidential bearing on the design question.

scholarly journals BEKENSTEIN BOUND OF INFORMATION NUMBER N AND ITS RELATION TO COSMOLOGICAL PARAMETERS IN A UNIVERSE WITH AND WITHOUT COSMOLOGICAL CONSTANT

2013 ◽  
Vol 28 (19) ◽  
pp. 1350077 ◽  
Author(s):  
IOANNIS HARANAS ◽  
IOANNIS GKIGKITZIS
Keyword(s):  
Cosmological Constant ◽  
Physical System ◽  
Cosmological Parameters ◽  
Hubble Constant ◽  
Short Paper ◽  
Information Number ◽  
Gravitating Systems ◽  
Two Universes ◽  
Cosmological Constants ◽  
The Universe

Bekenstein has obtained an upper limit on the entropy S, and from that, an information number bound N is deduced. In other words, this is the information contained within a given finite region of space that includes a finite amount of energy. Similarly, this can be thought as the maximum amount of information required to perfectly describe a given physical system down to its quantum level. If the energy and the region of space are finite then the number of information N required in describing the physical system is also finite. In this short paper, two information number bounds are derived and compared for two types of universe. First, a universe without a cosmological constant Λ and second a universe with a cosmological constant Λ are investigated. This is achieved with the derivation of two different relations that connect the Hubble constant and cosmological constants to the number of information N. We find that the number of information N involved in the two universes are identical or N2 = N2Λ, and that the total mass of the universe scales as the square root of the information number N, containing. an information number N of the order of 10122. Finally, we expressed Calogero's quantization action as a function of the number of information N. We also have found that in self-gravitating systems the number of information N in nats is the ratio of the total kinetic to total thermal energy of the system.

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