scholarly journals Observational signatures of near-extremal Kerr-like black holes in a modified gravity theory at the Event Horizon Telescope

2018 ◽  
Vol 98 (8) ◽  
Author(s):  
Minyong Guo ◽  
Niels A. Obers ◽  
Haopeng Yan
Keyword(s):  
Black Holes ◽  
Event Horizon ◽  
Modified Gravity ◽  
Gravity Theory ◽  
Modified Gravity Theory

scholarly journals A Modified Gravity Theory: Null Aether

2019 ◽  
Vol 71 (3) ◽  
pp. 312 ◽  
Author(s):  
Metin Gürses ◽  
Çetin Şentürk
Keyword(s):  
Modified Gravity ◽  
Gravity Theory ◽  
Modified Gravity Theory

MODIFIED GRAVITY THEORY DUE TO POSITIVE AS WELL AS NEGATIVE CURVATURE INDUCED ACCELERATION

2012 ◽  
Vol 21 (02) ◽  
pp. 1250012
Author(s):  
PRIYADARSHI MAJUMDAR
Keyword(s):  
Dark Energy ◽  
Modified Gravity ◽  
Negative Curvature ◽  
Gravity Theory ◽  
Cosmic Acceleration ◽  
Late Time ◽  
Negative Power ◽  
Modified Gravity Theory ◽  
Phase Q ◽  
The Universe

We formulate a modified gravity theory that eliminates the need for dark energy and is stable for a Lagrangian containing R, R2 as well as 1/R terms (i.e. nonlinear contributions of the Ricci curvature with a non-analytic model of f(R) at R = 0) without considering any matter-dominated era. The terms with positive powers (1, 2) of the curvature support the inflationary epoch while the terms with negative power (-1) serves as effective dark energy, supporting current cosmic acceleration. We present a few analytical solutions of evolution equation for the deceleration parameter q as a function of Hubble parameter H and time t; specially in one solution, the universe evolves continuously from q = 1 (a radiation-dominated epoch) to q = -1/2 (dark-energy-dominated late-time accelerating phase) when the universe is sufficiently old. The solution is supported by numerical results. The transition from the decelerated (q > 0) to the accelerated phase (q < 0) of expansion takes place smoothly without having to resort to a study of asymptotic behavior.

scholarly journals EFFECTS OF CHERN–SIMONS CORRECTIONS ON CONSERVED QUANTITIES OF RELATIVISTIC FLUID

2010 ◽  
Vol 25 (31) ◽  
pp. 2655-2666
Author(s):  
KOHKICHI KONNO ◽  
TOYOKI MATSUYAMA ◽  
SATOSHI TANDA
Keyword(s):  
Fluid Flow ◽  
Modified Gravity ◽  
Gravity Theory ◽  
Conserved Quantities ◽  
Maxwell Theory ◽  
Relativistic Fluid ◽  
Modified Gravity Theory ◽  
Chern Simons

We consider relativistic fluid flow under Chern–Simons modified Maxwell theory and under Chern–Simons modified gravity theory. We take account of the effects of Chern–Simons corrections on the quantities of fluid flow that is conserved without the Chern–Simons corrections. We find that the conservations of several quantities are generally broken by the Chern–Simons corrections.

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