scholarly journals Spatial curvature sensitivity to local H0 from the Cepheid distance ladder

2022 ◽  
Vol 33 ◽  
pp. 10-13
Author(s):  
Ella Zuckerman ◽  
Luis A. Anchordoqui
Keyword(s):  
Spatial Curvature

scholarly journals DARK MATTER, AND ITS DARKNESS

2006 ◽  
Vol 15 (12) ◽  
pp. 2267-2278 ◽  
Author(s):  
D. V. AHLUWALIA-KHALILOVA
Keyword(s):  
Dark Matter ◽  
Standard Model ◽  
Cosmological Constant ◽  
Model Material ◽  
Representation Space ◽  
Spatial Curvature ◽  
The Standard Model ◽  
General Relativistic ◽  
Relativistic Description ◽  
Friedmann Robertson Walker

Assuming the validity of the general relativistic description of gravitation on astrophysical and cosmological length scales, we analytically infer that the Friedmann–Robertson–Walker cosmology with Einsteinian cosmological constant, and a vanishing spatial curvature constant, unambiguously requires a significant amount of dark matter. This requirement is consistent with other indications for dark matter. The same space–time symmetries that underlie the freely falling frames of Einsteinian gravity also provide symmetries which, for the spin one half representation space, furnish a novel construct that carries extremely limited interactions with respect to the terrestrial detectors made of the standard model material. Both the "luminous" and "dark" matter turn out to be residents of the same representation space but they derive their respective "luminosity" and "darkness" from either belonging to the sector with (CPT)2 = +𝟙, or to the sector with (CPT)2 = -𝟙.

scholarly journals Model-independent constraints on cosmic curvature: implication from the future space gravitational-wave antenna DECIGO

2021 ◽  
Vol 81 (1) ◽  
Author(s):  
Xiaogang Zheng ◽  
Shuo Cao ◽  
Yuting Liu ◽  
Marek Biesiada ◽  
Tonghua Liu ◽  
...  
Keyword(s):  
Gravitational Wave ◽  
Future Generation ◽  
Spatial Curvature ◽  
Hubble Diagram ◽  
Einstein Telescope ◽  
Future Space ◽  
Local Measurements ◽  
New Type ◽  
Model Independent ◽  
Hubble Parameters

AbstractIn order to estimate cosmic curvature from cosmological probes like standard candles, one has to measure the luminosity distance $$D_L(z)$$ D L ( z ) , its derivative with respect to redshift $$D'_L(z)$$ D L ′ ( z ) and the expansion rate H(z) at the same redshift. In this paper, we study how such idea could be implemented with future generation of space-based DECi-hertz Interferometer Gravitational-wave Observatory (DECIGO), in combination with cosmic chronometers providing cosmology-independent H(z) data. Our results show that for the Hubble diagram of simulated DECIGO data acting as a new type of standard siren, it would be able to constrain cosmic curvature with the precision of $$\varDelta \varOmega _k= 0.09$$ Δ Ω k = 0.09 with the currently available sample of 31 measurements of Hubble parameters. In the framework of the third generation ground-based gravitational wave detectors, the spatial curvature is constrained to be $$\varDelta \varOmega _k= 0.13$$ Δ Ω k = 0.13 for Einstein Telescope (ET). More interestingly, compared to other approaches aiming for model-independent estimations of spatial curvature, our analysis also achieve the reconstruction of the evolution of $$\varOmega _k(z)$$ Ω k ( z ) , in the framework of a model-independent method of Gaussian processes (GP) without assuming a specific form. Therefore, one can expect that the newly emerged gravitational wave astronomy can become useful in local measurements of cosmic curvature using distant sources.

scholarly journals Using Spatial Curvature with H ii Galaxies and Cosmic Chronometers to Explore the Tension in H 0

2019 ◽  
Vol 881 (2) ◽  
pp. 137 ◽  
Author(s):  
Cheng-Zong Ruan ◽  
Fulvio Melia ◽  
Yu Chen ◽  
Tong-Jie Zhang
Keyword(s):  
Spatial Curvature

scholarly journals Quadratic integrals of a multi-scalar cosmological model

2020 ◽  
Vol 35 (10) ◽  
pp. 2050068 ◽  
Author(s):  
Sameerah Jamal
Keyword(s):  
Scalar Field ◽  
Cosmological Model ◽  
Conservation Laws ◽  
Analytical Solutions ◽  
Physical System ◽  
Noether Symmetries ◽  
Spatial Curvature ◽  
Special Case ◽  
Friedmann Robertson Walker ◽  
Field Integral

In the context of Friedmann–Robertson–Walker (FRW) spacetime with zero spatial curvature, we consider a multi-scalar tensor cosmology model under the pretext of obtaining quadratic conservation laws. We propose two new interaction potentials of the scalar field. Integral to this task is the existence of dynamical Noether symmetries which are Lie–Bäcklund transformations of the physical system. Finally, analytical solutions of the field are found corresponding to each new model. In one of the models, we find that the scale factor mimics [Formula: see text]-cosmology in a special case.

scholarly journals On the Necessity of Phantom Fields for Solving the Horizon Problem in Scalar Cosmologies

Universe ◽  
2019 ◽  
Vol 5 (3) ◽  
pp. 76 ◽  
Author(s):  
Davide Fermi ◽  
Massimo Gengo ◽  
Livio Pizzocchero
Keyword(s):  
Arbitrary Dimension ◽  
Energy Conditions ◽  
Solvable Models ◽  
Action Functional ◽  
Spatial Curvature ◽  
Horizon Problem ◽  
Particle Horizon ◽  
Perfect Fluids ◽  
The Universe ◽  
Phantom Fields

We discuss the particle horizon problem in the framework of spatially homogeneous and isotropic scalar cosmologies. To this purpose we consider a Friedmann–Lemaître–Robertson–Walker (FLRW) spacetime with possibly non-zero spatial sectional curvature (and arbitrary dimension), and assume that the content of the universe is a family of perfect fluids, plus a scalar field that can be a quintessence or a phantom (depending on the sign of the kinetic part in its action functional). We show that the occurrence of a particle horizon is unavoidable if the field is a quintessence, the spatial curvature is non-positive and the usual energy conditions are fulfilled by the perfect fluids. As a partial converse, we present three solvable models where a phantom is present in addition to a perfect fluid, and no particle horizon appears.

DETECTION OF THE SPATIAL CURVATURE EFFECTS THROUGH PHYSICAL PHENOMENA: THE NONLINEAR COHERENT STATES APPROACH

2012 ◽  
Vol 09 (01) ◽  
pp. 1250009 ◽  
Author(s):  
A. MAHDIFAR ◽  
R. ROKNIZADEH ◽  
M. H. NADERI
Keyword(s):  
Hilbert Space ◽  
Geometric Phase ◽  
Coherent States ◽  
Transition Probability ◽  
Physical Space ◽  
Spatial Curvature ◽  
Curved Space ◽  
Curvature Effects ◽  
Projective Hilbert Space ◽  
Physical Phenomena

In this paper, by using the nonlinear coherent states approach, we find a relation between the geometric structure of the physical space and the geometry of the corresponding projective Hilbert space. To illustrate the approach, we explore the quantum transition probability and the geometric phase in the curved space.

scholarly journals A precise extragalactic test of General Relativity

Science ◽  
2018 ◽  
Vol 360 (6395) ◽  
pp. 1342-1346 ◽  
Author(s):  
Thomas E. Collett ◽  
Lindsay J. Oldham ◽  
Russell J. Smith ◽  
Matthew W. Auger ◽  
Kyle B. Westfall ◽  
...  
Keyword(s):  
General Relativity ◽  
Solar System ◽  
Long Range ◽  
Weak Field ◽  
Gravitational Lens ◽  
Stellar Kinematics ◽  
Spatial Curvature ◽  
Spatially Resolved ◽  
Consistent Model ◽  
Self Consistent

Einstein’s theory of gravity, General Relativity, has been precisely tested on Solar System scales, but the long-range nature of gravity is still poorly constrained. The nearby strong gravitational lens ESO 325-G004 provides a laboratory to probe the weak-field regime of gravity and measure the spatial curvature generated per unit mass, γ. By reconstructing the observed light profile of the lensed arcs and the observed spatially resolved stellar kinematics with a single self-consistent model, we conclude that γ = 0.97 ± 0.09 at 68% confidence. Our result is consistent with the prediction of 1 from General Relativity and provides a strong extragalactic constraint on the weak-field metric of gravity.

scholarly journals Spatial curvature at the sound horizon

2020 ◽  
Vol 2020 (02) ◽  
pp. 034-034 ◽  
Author(s):  
Guus Avis ◽  
Sadra Jazayeri ◽  
Enrico Pajer ◽  
Jakub Supeł
Keyword(s):  
Spatial Curvature
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