scholarly journals THE FAILURES OF THE STANDARD MODEL OF COSMOLOGY REQUIRE A NEW PARADIGM

2012 ◽  
Vol 21 (14) ◽  
pp. 1230003 ◽  
Author(s):  
PAVEL KROUPA ◽  
MARCEL PAWLOWSKI ◽  
MORDEHAI MILGROM
Keyword(s):  
Standard Model ◽  
Cold Dark Matter ◽  
Universal Constant ◽  
Classical Dynamics ◽  
New Paradigm ◽  
Local Systems ◽  
Modified Newtonian Dynamics ◽  
Newtonian Dynamics ◽  
The Standard Model ◽  
The Universe

Cosmological models that invoke warm or cold dark matter cannot explain observed regularities in the properties of dwarf galaxies, their highly anisotropic spatial distributions, nor the correlation between observed mass discrepancies and acceleration. These problems with the standard model of cosmology have deep implications, in particular in combination with the observation that the data are excellently described by Modified Newtonian Dynamics (MOND). MOND is a classical dynamics theory which explains the mass discrepancies in galactic systems, and in the universe at large, without invoking 'dark' entities. MOND introduces a new universal constant of nature with the dimensions of acceleration, a0, such that the pre-MONDian dynamics is valid for accelerations a ≫ a0, and the deep MONDian regime is obtained for a ≪ a0, where spacetime scale invariance is invoked. Remaining challenges for MOND are (i) explaining fully the observed mass discrepancies in galaxy clusters, and (ii) the development of a relativistic theory of MOND that will satisfactorily account for cosmology. The universal constant a0 turns out to have an intriguing connection with cosmology: ā0 ≡ 2πa0 ≈ cH0 ≈ c2(Λ/3)1/2. This may point to a deep connection between cosmology and internal dynamics of local systems.

scholarly journals GENERATING SMALL NUMBERS BY TUNNELING IN MULTI-THROAT COMPACTIFICATIONS

2004 ◽  
Vol 19 (16) ◽  
pp. 2657-2704 ◽  
Author(s):  
SAVAS DIMOPOULOS ◽  
SHAMIT KACHRU ◽  
NEMANJA KALOPER ◽  
ALBION LAWRENCE ◽  
EVA SILVERSTEIN
Keyword(s):  
Standard Model ◽  
Cold Dark Matter ◽  
Dark Matter Particle ◽  
Susy Breaking ◽  
Nuclear Decay ◽  
Hierarchy Problem ◽  
Higher Dimensional ◽  
The Standard Model ◽  
The Universe ◽  
Hubble Time

A generic F-theory compactification containing many D3 branes develops multiple brane throats. The interaction of observers residing inside different throats involves tunneling suppression and as a result, is very weak. This suggests a new mechanism for generating small numbers in Nature. One application is to the hierarchy problem: large supersymmetry breaking near the unification scale inside a shallow throat causes TeV-scale SUSY-breaking inside the standard-model throat. Another application, inspired by nuclear-decay, is in designing naturally long-lived particles: a cold dark matter particle residing near the standard model brane decays to an approximate CFT-state of a longer throat within a Hubble time. This suggests that most of the mass of the universe today could consist of CFT-matter and may soften structure formation at sub-galactic scales. The tunneling calculation demonstrates that the coupling between two throats is dominated by higher dimensional modes and consequently is much larger than a naive application of holography might suggest.

scholarly journals ℋolographic 𝒩aturalness

2020 ◽  
Vol 29 (14) ◽  
pp. 2050084
Author(s):  
Andrea Addazi
Keyword(s):  
Standard Model ◽  
Cosmological Constant ◽  
Particle Physics ◽  
Intrinsic Disorder ◽  
High Energy ◽  
Holographic Principle ◽  
New Paradigm ◽  
The Standard Model ◽  
The Universe ◽  
Decoherence Effect

The [Formula: see text]olographic [Formula: see text]aturalness ([Formula: see text]) is a new paradigm towards an explanation of the Cosmological Constant (CC) and the Higgs Hierarchy (HH) in the Universe. Motivated by the Holographic Principle, and inspired by the (A)dS/CFT correspondence, we elaborate on the possibility and on the cosmological consequences of a fundamental intrinsic disorder and temperature in vacuo. We postulate that the zero vacuum entropy is provided by a large number of quantum hair fields, the hairons. The quantum hairon gas in spacetime induces an effective decoherence effect to the Standard Model (SM) particle sector. This is leading to an entropic reinterpretation of UV divergent contributions to CC and HH: we will show that, in both the cases, the large number of re-scatterings on the hairon ensamble suppresses any radiative instabilities. The CC and HH problems are illusions envisaged by a conscious observer, having access on the limited amount of information from SM tests: both the issues are originated from our ignorance of the hidden entropy intrinsically stored in the spacetime. The [Formula: see text] suggests to search for effective decoherence effects in particle physics observables such as effective CPT, Unitarity and Energy violations. Regarding the HH, the [Formula: see text] does not introduce any new particles or interactions around the TeV-scale: we do not expect for any signatures, at LHC and any future high energy colliders, related to the Higgs UV completion in a Wilsonian sense.

An Interview with the Physicist that Her Head in the Universe and Both Feet on the Earth

2019 ◽  
Author(s):  
Adib Rifqi Setiawan
Keyword(s):  
Standard Model ◽  
Particle Physics ◽  
Space Time ◽  
Additional Dimension ◽  
The Earth ◽  
The Standard Model ◽  
The Universe

Put simply, Lisa Randall’s job is to figure out how the universe works, and what it’s made of. Her contributions to theoretical particle physics include two models of space-time that bear her name. The first Randall–Sundrum model addressed a problem with the Standard Model of the universe, and the second concerned the possibility of a warped additional dimension of space. In this work, we caught up with Randall to talk about why she chose a career in physics, where she finds inspiration, and what advice she’d offer budding physicists. This article has been edited for clarity. My favourite quote in this interview is, “Figure out what you enjoy, what your talents are, and what you’re most curious to learn about.” If you insterest in her work, you can contact her on Twitter @lirarandall.

An Interview with the Physicist that Her Head in the Universe and Both Feet on the Earth

2019 ◽  
Author(s):  
Adib Rifqi Setiawan
Keyword(s):  
Standard Model ◽  
Particle Physics ◽  
Space Time ◽  
Additional Dimension ◽  
The Earth ◽  
The Standard Model ◽  
The Universe

Put simply, Lisa Randall’s job is to figure out how the universe works, and what it’s made of. Her contributions to theoretical particle physics include two models of space-time that bear her name. The first Randall–Sundrum model addressed a problem with the Standard Model of the universe, and the second concerned the possibility of a warped additional dimension of space. In this work, we caught up with Randall to talk about why she chose a career in physics, where she finds inspiration, and what advice she’d offer budding physicists. This article has been edited for clarity. My favourite quote in this interview is, “Figure out what you enjoy, what your talents are, and what you’re most curious to learn about.” If you insterest in her work, you can contact her on Twitter @lirarandall.

scholarly journals Complete leading-order standard model corrections to quantum leptogenesis

2020 ◽  
Vol 2020 (9) ◽  
Author(s):  
Paul Frederik Depta ◽  
Andreas Halsch ◽  
Janine Hütig ◽  
Sebastian Mendizabal ◽  
Owe Philipsen
Keyword(s):  
Standard Model ◽  
Gauge Coupling ◽  
Thermal Bath ◽  
Leading Order ◽  
Boltzmann Equations ◽  
The Standard Model ◽  
Majorana Neutrinos ◽  
Infinite Loop ◽  
First Time ◽  
The Universe

Abstract Thermal leptogenesis, in the framework of the standard model with three additional heavy Majorana neutrinos, provides an attractive scenario to explain the observed baryon asymmetry in the universe. It is based on the out-of-equilibrium decay of Majorana neutrinos in a thermal bath of standard model particles, which in a fully quantum field theoretical formalism is obtained by solving Kadanoff-Baym equations. So far, the leading two-loop contributions from leptons and Higgs particles are included, but not yet gauge corrections. These enter at three-loop level but, in certain kinematical regimes, require a resummation to infinite loop order for a result to leading order in the gauge coupling. In this work, we apply such a resummation to the calculation of the lepton number density. The full result for the simplest “vanilla leptogenesis” scenario is by $$ \mathcal{O} $$ O (1) increased compared to that of quantum Boltzmann equations, and for the first time permits an estimate of all theoretical uncertainties. This step completes the quantum theory of leptogenesis and forms the basis for quantitative evaluations, as well as extensions to other scenarios.

scholarly journals Relativistic Cosmology with an Introduction to Inflation

Universe ◽  
2021 ◽  
Vol 7 (8) ◽  
pp. 276
Author(s):  
Muhammad Zahid Mughal ◽  
Iftikhar Ahmad ◽  
Juan Luis García Guirao
Keyword(s):  
Standard Model ◽  
Early Universe ◽  
Large Scale ◽  
Initial Conditions ◽  
Big Bang ◽  
Relativistic Cosmology ◽  
The Standard Model ◽  
Big Bang Model ◽  
The Big Bang ◽  
The Universe

In this review article, the study of the development of relativistic cosmology and the introduction of inflation in it as an exponentially expanding early phase of the universe is carried out. We study the properties of the standard cosmological model developed in the framework of relativistic cosmology and the geometric structure of spacetime connected coherently with it. The geometric properties of space and spacetime ingrained into the standard model of cosmology are investigated in addition. The big bang model of the beginning of the universe is based on the standard model which succumbed to failure in explaining the flatness and the large-scale homogeneity of the universe as demonstrated by observational evidence. These cosmological problems were resolved by introducing a brief acceleratedly expanding phase in the very early universe known as inflation. The cosmic inflation by setting the initial conditions of the standard big bang model resolves these problems of the theory. We discuss how the inflationary paradigm solves these problems by proposing the fast expansion period in the early universe. Further inflation and dark energy in fR modified gravity are also reviewed.

MOND as the basis for an extended theory of gravity

2015 ◽  
Vol 93 (2) ◽  
pp. 217-231 ◽  
Author(s):  
S. Mendoza
Keyword(s):  
Equivalence Principle ◽  
Clusters Of Galaxies ◽  
Relativistic Theory Of Gravity ◽  
Modified Newtonian Dynamics ◽  
Newtonian Dynamics ◽  
Acceleration Of The Universe ◽  
Theory Of Gravity ◽  
The Universe ◽  
Geometric Nature ◽  
Bending Of Light

This review describes why the geometric nature of space–time, the Einstein equivalence principle, and the geodesic motion of particles show the possibility of building an extended relativistic theory of gravity on regions where the Tully–Fisher law is valid. It is also shown how a metric construction of gravity can have a modified Newtonian dynamics behaviour compatible with the Tully–Fisher law and the bending of light observed in individual, groups, and clusters of galaxies. It is also reviewed how this metric theory of gravity fits reasonably well on cosmological scales explaining the current acceleration of the universe.

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