A stealth defect of spacetime

2018 ◽  
Vol 33 (22) ◽  
pp. 1850127 ◽  
Author(s):  
F. R. Klinkhamer ◽  
J. M. Queiruga
Keyword(s):  
Energy Density ◽  
Long Range ◽  
Mass Term ◽  
Matter Field ◽  
Skyrme Model ◽  
Gravitational Mass ◽  
Positive Energy ◽  
Type Solution ◽  
Matter Fields

We discuss a special type of Skyrmion spacetime-defect solution, which has a positive energy density of the matter fields but a vanishing asymptotic gravitational mass. With a mass term for the matter field added to the action (corresponding to massive “pions” in the Skyrme model), this particular soliton-type solution has no long-range fields and can appropriately be called a “stealth defect”.

scholarly journals Hierarchical structure of physical Yukawa couplings from matter field Kähler metric

2021 ◽  
Vol 2021 (7) ◽  
Author(s):  
Keiya Ishiguro ◽  
Tatsuo Kobayashi ◽  
Hajime Otsuka
Keyword(s):  
String Theory ◽  
Hierarchical Structure ◽  
Matter Field ◽  
Heterotic String ◽  
Heterotic String Theory ◽  
Kähler Metric ◽  
Yukawa Couplings ◽  
String Compactifications ◽  
Kahler Metric ◽  
Matter Fields

Abstract We study the impacts of matter field Kähler metric on physical Yukawa couplings in string compactifications. Since the Kähler metric is non-trivial in general, the kinetic mixing of matter fields opens a new avenue for realizing a hierarchical structure of physical Yukawa couplings, even when holomorphic Yukawa couplings have the trivial structure. The hierarchical Yukawa couplings are demonstrated by couplings of pure untwisted modes on toroidal orbifolds and their resolutions in the context of heterotic string theory with standard embedding. Also, we study the hierarchical couplings among untwisted and twisted modes on resolved orbifolds.

scholarly journals TRAVERSABLE WORMHOLES IN (2+1) AND (3+1) DIMENSIONS WITH A COSMOLOGICAL CONSTANT

1995 ◽  
Vol 04 (02) ◽  
pp. 231-245 ◽  
Author(s):  
M.S.R. DELGATY ◽  
R.B. MANN
Keyword(s):  
Energy Density ◽  
Cosmological Constant ◽  
Positive Energy ◽  
Mass Energy ◽  
Field Equations ◽  
Dimensional Solution ◽  
Partial Stability ◽  
Traversable Wormholes ◽  
Spacetime Curvature ◽  
Radial Tension

Macroscopic traversable wormhole solutions to Einstein’s field equations in (2+1) and (3+1) dimensions with a cosmological constant are investigated. Ensuring traversability severely constrains the material used to generate the wormhole’s spacetime curvature. Although the presence of a cosmological constant modifies to some extent the type of matter permitted [for example it is possible to have a positive energy density for the material threading the throat of the wormhole in (2+1) dimensions], the material must still be “exotic,” that is matter with a larger radial tension than total mass-energy density multiplied by c2. Two specific solutions are applied to the general cases and a partial stability analysis of a (2+1) dimensional solution is explored.

scholarly journals Positive Energy Driven CTCs In ADM 3+1 Space – Time of Unprotected Chronology

2021 ◽  
Author(s):  
Deep Bhattacharjee
Keyword(s):  
Energy Density ◽  
Energy Momentum Tensor ◽  
Momentum Tensor ◽  
Space Time ◽  
Exotic Matter ◽  
Positive Energy ◽  
Spacelike Hypersurfaces ◽  
Stress Energy ◽  
Maxwell Fields ◽  
Stress Energy Momentum Tensor

Chronology unprotected mechanisms are considered with a very low gravitational polarization to make the wormhole traversal with positive energy density everywhere. No need of exotic matter has been considered with the assumption of the Einstein-Dirac-Maxwell Fields, encountering above the non-zero stress-energy-momentum tensor through spacelike hypersurfaces by a hyperbolic coordinate shift.

scholarly journals Fermi Degenerate Antineutrino Star Model of Dark Energy

2020 ◽  
Vol 2020 ◽  
pp. 1-11 ◽  
Author(s):  
Tom F. Neiser
Keyword(s):  
Dark Energy ◽  
Energy Density ◽  
Background Radiation ◽  
Mass Density ◽  
High Energy ◽  
Big Bang ◽  
Gravitational Mass ◽  
High Energy Density ◽  
Star Model ◽  
Λcdm Model

When the Large Hadron Collider resumes operations in 2021, several experiments will directly measure the motion of antihydrogen in free fall for the first time. Our current understanding of the universe is not yet fully prepared for the possibility that antimatter has negative gravitational mass. This paper proposes a model of cosmology, where the state of high energy density of the big bang is created by the collapse of an antineutrino star that has exceeded its Chandrasekhar limit. To allow the first neutrino stars and antineutrino stars to form naturally from an initial quantum vacuum state, it helps to assume that antimatter has negative gravitational mass. This assumption may also be helpful to identify dark energy. The degenerate remnant of an antineutrino star can today have an average mass density that is similar to the dark energy density of the ΛCDM model. When in hydrostatic equilibrium, this antineutrino star remnant can emit isothermal cosmic microwave background radiation and accelerate matter radially. This model and the ΛCDM model are in similar quantitative agreement with supernova distance measurements. Therefore, this model is useful as a purely academic exercise and as preparation for possible future discoveries.

scholarly journals Near-BPS baby Skyrmions

2020 ◽  
Vol 2020 (11) ◽  
Author(s):  
Sven Bjarke Gudnason ◽  
Marco Barsanti ◽  
Stefano Bolognesi
Keyword(s):  
Binding Energy ◽  
Topological Charge ◽  
Harmonic Maps ◽  
Single Point ◽  
Pion Mass ◽  
Mass Term ◽  
Skyrme Model ◽  
Classical Solutions ◽  
Leading Order ◽  
Area Preserving

Abstract We consider the baby-Skyrme model in the regime close to the so-called restricted baby-Skyrme model, which is a BPS model with area-preserving diffeomorphism invariance. The perturbation takes the form of the standard kinetic Dirichlet term with a small coefficient ϵ. Classical solutions of this model, to leading order in ϵ, are called restricted harmonic maps. In the BPS limit (ϵ → 0) of the model with the potential being the standard pion-mass term, the solution with unit topological charge is a compacton. Using analytical and numerical arguments we obtain solutions to the problem for topological sectors greater than one. We develop a perturbative scheme in ϵ with which we can calculate the corrections to the BPS mass. The leading order ($$ \mathcal{O}\left({\upepsilon}^1\right) $$ O ϵ 1 ) corrections show that the baby Skyrmion with topological charge two is energetically preferred. The binding energy requires us to go to the third order in ϵ to capture the relevant terms in perturbation theory, however, the binding energy contributes to the total energy at order ϵ2. We find that the baby Skyrmions — in the near-BPS regime — are compactons of topological charge two, that touch each other on their periphery at a single point and with orientations in the attractive channel.

scholarly journals The 1-soliton in theSO(3) gauged Skyrme model with mass term

Nonlinearity ◽  
2002 ◽  
Vol 15 (2) ◽  
pp. 385-392 ◽  
Author(s):  
Y Brihaye ◽  
J Burzlaff ◽  
V Paturyan ◽  
D H Tchrakian
Keyword(s):  
Mass Term ◽  
Skyrme Model

scholarly journals Stochastic fluctuations of bosonic dark matter

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Gary P. Centers ◽  
John W. Blanchard ◽  
Jan Conrad ◽  
Nataniel L. Figueroa ◽  
Antoine Garcon ◽  
...  
Keyword(s):  
Dark Matter ◽  
Particle Physics ◽  
Laboratory Experiments ◽  
Coherence Time ◽  
Matter Field ◽  
Beyond The Standard Model ◽  
Bosonic Field ◽  
Stochastic Fluctuations ◽  
The Standard Model ◽  
Matter Fields

AbstractNumerous theories extending beyond the standard model of particle physics predict the existence of bosons that could constitute dark matter. In the standard halo model of galactic dark matter, the velocity distribution of the bosonic dark matter field defines a characteristic coherence time τc. Until recently, laboratory experiments searching for bosonic dark matter fields have been in the regime where the measurement time T significantly exceeds τc, so null results have been interpreted by assuming a bosonic field amplitude Φ0 fixed by the average local dark matter density. Here we show that experiments operating in the T ≪ τc regime do not sample the full distribution of bosonic dark matter field amplitudes and therefore it is incorrect to assume a fixed value of Φ0 when inferring constraints. Instead, in order to interpret laboratory measurements (even in the event of a discovery), it is necessary to account for the stochastic nature of such a virialized ultralight field. The constraints inferred from several previous null experiments searching for ultralight bosonic dark matter were overestimated by factors ranging from 3 to 10 depending on experimental details, model assumptions, and choice of inference framework.

scholarly journals Freely falling observer and black hole radiation

2014 ◽  
Vol 29 (11) ◽  
pp. 1450052 ◽  
Author(s):  
Wontae Kim ◽  
Edwin J. Son
Keyword(s):  
Black Hole ◽  
Energy Density ◽  
Event Horizon ◽  
Negative Energy ◽  
Positive Energy ◽  
Energy Curve ◽  
Zero Energy ◽  
Negative Energy Density ◽  
Black Hole Radiation

We find radiation in an infalling frame and present an explicit analytic evidence of the failure of no drama condition by showing that an infalling observer finds an infinite negative energy density at the event horizon. The negative and positive energy density regions are divided by the newly defined zero-energy curve (ZEC). The evaporating black hole is surrounded by the negative energy which can also be observed in the infalling frame.

scholarly journals INTRINSICALLY QUANTUM-MECHANICAL GRAVITY AND THE COSMOLOGICAL CONSTANT PROBLEM

2011 ◽  
Vol 26 (32) ◽  
pp. 2375-2389 ◽  
Author(s):  
PHILIP D. MANNHEIM
Keyword(s):  
Cosmological Constant ◽  
Conformal Symmetry ◽  
Zero Point ◽  
Dynamical Symmetry ◽  
Matter Field ◽  
Quantum Mechanical ◽  
Conformal Invariant ◽  
Cosmological Constant Problem ◽  
The Universe ◽  
Matter Fields

We propose that gravity be intrinsically quantum-mechanical, so that in the absence of quantum mechanics the geometry of the universe would be Minkowski. We show that in such a situation gravity does not require any independent quantization of its own, with it being quantized simply by virtue of its being coupled to the quantized matter fields that serve as its source. We show that when the gravitational and matter fields possess an underlying conformal symmetry, the gravitational field and fermionic matter-field zero-point fluctuations cancel each other identically. Then, when the fermions acquire mass by a dynamical symmetry breaking procedure that induces a cosmological constant in such conformal theories, the zero-point fluctuations readjust so as to cancel the induced cosmological constant identically. The zero-point vacuum problem and the cosmological constant vacuum problems thus mutually solve each other. We illustrate our ideas in a completely solvable conformal-invariant model, namely two-dimensional quantum Einstein gravity coupled to a Nambu–Jona-Lasinio self-consistent fermion.

scholarly journals SUPERSYMMETRIC BAROTROPIC FRW MODEL AND DARK ENERGY

2009 ◽  
Vol 24 (16) ◽  
pp. 1257-1266
Author(s):  
J. J. ROSALES ◽  
V. I. TKACH
Keyword(s):  
Dark Energy ◽  
Energy Density ◽  
Perfect Fluid ◽  
Vacuum Energy ◽  
Matter Field ◽  
Vacuum Energy Density ◽  
Square Root ◽  
Frw Universe ◽  
Frw Model

Using the superfield approach we construct the n = 2 supersymmetric Lagrangian for the FRW Universe with barotropic perfect fluid as matter field. The obtained supersymmetric algebra allowed us to take the square root of the Wheeler–DeWitt equation and solve the corresponding quantum constraint. This model leads to the relation between the vacuum energy density and the energy density of the dust matter.

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