scholarly journals Computability of the causal boundary by using isocausality

2013 ◽  
Vol 30 (7) ◽  
pp. 075009 ◽  
Author(s):  
J L Flores ◽  
J Herrera ◽  
M Sánchez
Keyword(s):  
Causal Boundary

Causal boundary for strongly causal spacetimes

1988 ◽  
Vol 5 (1) ◽  
pp. 121-134 ◽  
Author(s):  
L B Szabados
Keyword(s):  
Causal Boundary

The Causal Boundary Of Standard Stationary Spacetimes

2009 ◽  
Author(s):  
José L. Flores ◽  
Kerstin E. Kunze ◽  
Marc Mars ◽  
Miguel Angel Vázquez-Mozo
Keyword(s):  
Causal Boundary ◽  
Stationary Spacetimes

The causal boundary of space-times

1971 ◽  
Vol 1 (3) ◽  
pp. 247-259 ◽  
Author(s):  
Hans -J�rgen Seifert
Keyword(s):  
Causal Boundary

On the usage of the 2D-AR-model in texture completion scenarios with causal boundary conditions: A tutorial

2015 ◽  
Vol 32 ◽  
pp. 106-120 ◽  
Author(s):  
Martin Köppel ◽  
Dimitar Doshkov ◽  
Fabien Racape ◽  
Patrick Ndjiki-Nya ◽  
Thomas Wiegand
Keyword(s):  
Boundary Conditions ◽  
Ar Model ◽  
Causal Boundary

The causal boundary of the trousers space

1990 ◽  
Vol 7 (2) ◽  
pp. 149-161 ◽  
Author(s):  
S G Harris ◽  
T Dray
Keyword(s):  
Causal Boundary

scholarly journals The cosmological constant as a zero action boundary

2021 ◽  
Vol 502 (1) ◽  
pp. 436-444
Author(s):  
Enrique Gaztañaga
Keyword(s):  
Cosmological Constant ◽  
Modified Gravity ◽  
Cosmological Parameters ◽  
Average Density ◽  
Matter Density ◽  
Cosmic Acceleration ◽  
Perfect Fluid Solution ◽  
Cosmic Expansion ◽  
Causal Boundary ◽  
Boundary Force

ABSTRACT The cosmological constant Λ is usually interpreted as Dark Energy (DE) or modified gravity (MG). Here, we propose instead that Λ corresponds to a boundary term in the action of classical General Relativity. The action is zero for a perfect fluid solution and this fixes Λ to the average density ρ and pressure p inside a primordial causal boundary: Λ = 4πG <ρ+3p >. This explains both why the observed value of Λ is related to the matter density today and also why other contributions to Λ, such as DE or MG, do not produce cosmic expansion. Cosmic acceleration results from the repulsive boundary force that occurs when the expansion reaches the causal horizon. This universe is similar to the ΛCDM universe, except on the largest observable scales, where we expect departures from homogeneity/isotropy, such as CMB anomalies and variations in cosmological parameters indicated by recent observations.

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