scholarly journals Obtaining the time evolution for spherically symmetric Lemaître-Tolman-Bondi models given data on our past light cone

2009 ◽  
Vol 80 (12) ◽  
Author(s):  
M. E. Araújo ◽  
W. R. Stoeger
Keyword(s):  
Time Evolution ◽  
Light Cone ◽  
Spherically Symmetric ◽  
Past Light Cone

scholarly journals Evolution of cosmological horizons of wormhole cosmology

2020 ◽  
Vol 29 (12) ◽  
pp. 2050079
Author(s):  
Sung-Won Kim
Keyword(s):  
Light Cone ◽  
Dynamic Properties ◽  
Field Equations ◽  
The Past ◽  
Particle Horizon ◽  
Proper Distance ◽  
Apparent Horizons ◽  
Spatial Coordinates ◽  
Causal Structures ◽  
Past Light Cone

Recently, we solved Einstein’s field equations to obtain the exact solution of the cosmological model with the Morris–Thorne-type wormhole. We found the apparent horizons and analyzed their geometric natures, including the causal structures. We also derived the Hawking temperature near the apparent cosmological horizon. In this paper, we investigate the dynamic properties of the apparent horizons under the matter-dominated universe and lambda-dominated universe. As a more realistic universe, we also adopt the [Formula: see text]CDM universe which contains both the matter and lambda. The past light cone and the particle horizon are examined for what happens in the case of the model with wormhole. Since the spatial coordinates of the spacetime with the wormhole are limited outside the throat, the past light cone can be operated by removing the smaller-than-wormhole region. The past light cones without wormhole begin to start earlier than the past light cones with wormhole in conformal time-proper distance coordinates. The light cone consists of two parts: the information from our universe and the information from other universe or far distant region through the wormhole. Therefore, the particle horizon distance determined from the observer’s past light cone cannot be defined in a unique way.

Induced Quantum Fluctuations in the Spherically Symmetric Space–Time

1997 ◽  
Vol 12 (18) ◽  
pp. 3171-3180 ◽  
Author(s):  
Kamal K. Nandi ◽  
Anwarul Islam ◽  
James Evans
Keyword(s):  
Symmetric Space ◽  
Light Cone ◽  
Quantum Fluctuation ◽  
Quantum Fluctuations ◽  
Dynamical Variable ◽  
Nonrelativistic Limit ◽  
Space Time ◽  
Spherically Symmetric ◽  
Speed Of Light

In the Schwarzschild field due to a mass moving with velocity v → c0, where c0 is the speed of light in vacuum, the source-induced quantum fluctuation in the light cone exhibits consistency with the Aichelburg–Sexl solution while that in the metric dynamical variable does not. At the horizon, none of the fluctuations is proportional to anything finite. However, in the nonrelativistic limit (v → 0), known expressions follow.

scholarly journals Observing relativistic features in large-scale structure surveys – I: Multipoles of the power spectrum

2020 ◽  
Author(s):  
Caroline Guandalin ◽  
Julian Adamek ◽  
Philip Bull ◽  
Chris Clarkson ◽  
L Raul Abramo ◽  
...  
Keyword(s):  
Power Spectrum ◽  
Light Cone ◽  
Large Scale ◽  
Dark Matter Halos ◽  
The Past ◽  
Initial Application ◽  
Correct Estimation ◽  
Number Counts ◽  
Past Light Cone

Abstract Planned efforts to probe the largest observable distance scales in future cosmological surveys are motivated by a desire to detect relic correlations left over from inflation, and the possibility of constraining novel gravitational phenomena beyond General Relativity (GR). On such large scales, the usual Newtonian approaches to modelling summary statistics like the power spectrum and bispectrum are insufficient, and we must consider a fully relativistic and gauge-independent treatment of observables such as galaxy number counts in order to avoid subtle biases, e.g. in the determination of the fNL parameter. In this work, we present an initial application of an analysis pipeline capable of accurately modelling and recovering relativistic spectra and correlation functions. As a proof of concept, we focus on the non-zero dipole of the redshift-space power spectrum that arises in the cross-correlation of different mass bins of dark matter halos, using strictly gauge-independent observable quantities evaluated on the past light cone of a fully relativistic N-body simulation in a redshift bin 1.7 ≤ z ≤ 2.9. We pay particular attention to the correct estimation of power spectrum multipoles, comparing different methods of accounting for complications such as the survey geometry (window function) and evolution/bias effects on the past light cone, and discuss how our results compare with previous attempts at extracting novel GR signatures from relativistic simulations.

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