Search Results - "Mitra, Abhas"

On the Maximum Energy Release from Formation of Static Compact Objects by Mitra, Abhas, Singh, Krishna Kumar

“…Type II Supernova 1987A (SN 1987A), observed in 1987, released an energy of Q≈3×1053 erg. This huge energy is essentially the magnitude of gravitational…”
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Thermal Radiation from Compact Objects in Curved Space-Time by Mitra, Abhas, Singh, Krishna Kumar

“…We highlight here the fact that the distantly observed luminosity of a spherically symmetric compact star radiating thermal radiation isotropically is higher…”
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How to distinguish an actual astrophysical magnetized black hole mimicker from a true (theoretical) black hole by Mitra, Abhas, Corda, Christian, Mosquera Cuesta, Herman J.

“…We remind that the “ring down” features observed in the LIGO gravitational waves (GW) resulted from trembling of “photon spheres” ( R photon = 3 M , by using…”
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Interpretational conflicts between the static and non-static forms of the de Sitter metric by Mitra, Abhas

“…The de-Sitter metric is a special form of the non-static Friedmann metric and appears to be genuinely non-static since it describes the initial exponential…”
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Why the Rh = ct cosmology is unphysical and in fact a vacuum in disguise like the milne cosmology by Mitra, Abhas

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Why the R^sub h^ = ct cosmology is a vacuum solution in disguise and why all big bang models should be so by Mitra, Abhas

“…Recently, Melia and his coworkers have proposed the so-called R^sub h^ = ctcosmology where the scale factor of the universe is a(t) ... t and the spatial part…”
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Why the Big Bang Model does not allow inflationary and cyclic cosmologies though mathematically one can obtain any model with favourable assumptions by Mitra, Abhas

“…Various versions of standard Big Bang Model (BBM) including the current LCDM cosmology require an “inflationary” phase for the nascent universe (Δt∼10-32s)…”
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Testing Rh=ct cosmology from fundamental considerations: Is the Friedmann universe intrinsically flat by Mitra, Abhas

“…Recently Melia and Shevchuk (Mon Not R Astron Soc 419:2579, 2012 ) (MS) have proposed the so-called R h = c t cosmology where the “Gravitational Horizon” of…”
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Testing $$R_h=ct$$ R h = c t cosmology from fundamental considerations: Is the Friedmann universe intrinsically flat by Mitra, Abhas

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The fallacy of Oppenheimer Snyder collapse: no general relativistic collapse at all, no black hole, no physical singularity by Mitra, Abhas

“…By applying Birkhoff’s theorem to the problem of the general relativistic collapse of a uniform density dust, we directly show that the density of the dust ρ…”
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Einstein energy associated with the Friedmann–Robertson–Walker metric by Mitra, Abhas

“…Following Einstein’s definition of Lagrangian density and gravitational field energy density (Einstein in Ann Phys Lpz 49:806, 1916, Einstein in Phys Z 19:115,…”
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Friedmann-Robertson-Walker metric in curvature coordinates and its applications by Mitra, Abhas

“…For the first time, we express the general Friedmann-Robertson-Walker (FRW) metric ( k = +1, 0,−1) into explicit “Schwarzschild” or “Curvature” form, which is…”
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No uniform density star in general relativity by Mitra, Abhas

“…As per general relativity (GR), there cannot be any superluminal propagation of energy. And thus, the sound speed in a continuous medium, , must be subluminal…”
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The matter in the Big-Bang model is dust and not any arbitrary perfect fluid by Mitra, Abhas

“…We consider a spherically symmetric general relativistic perfect fluid in its comoving frame. It is found that, by integrating the local energy momentum…”
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Does pressure increase or decrease active gravitational mass density by Mitra, Abhas

“…At first sight, for a static fluid sphere, Effective Mass Energy Density (EMD) appears to be (ρ+3p/c2), where ρ is the bare mass density, p is the isotropic…”
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Macroscopic Form of the First Law of Thermodynamics for an Adibatically Evolving Non-singular Self-gravitating Fluid by Mitra, Abhas

“…We emphasize that the pressure related work appearing in a general relativistic first law of thermodynamics should involve proper volume element rather than…”
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Quantum information paradox: Real or fictitious? by Mitra, Abhas

“…One of the outstanding puzzles of theoretical physics is whether quantum information indeed gets lost in the case of black hole (BH) evaporation or accretion…”
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Revisiting the old problem of general-relativistic adiabatic collapse of a uniform-density self-gravitating sphere by Mitra, Abhas

“…The problem of general-relativistic adiabatic collapse of a uniform-density perfect sphere has been studied since Wyman (Phys. Rev. 70 , 396, (1946)) [1]…”
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Deriving Friedmann Robertson Walker metric and Hubble’s law from gravitational collapse formalism by Mitra, Abhas

“…In general relativity, one is supposed to derive the metric by solving the relevant Einstein equations. However, the metric for the…”
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Likely formation of general relativistic radiation pressure supported stars or ‘eternally collapsing objects’ by Mitra, Abhas, Glendenning, Norman K.

“…Hoyle & Fowler showed that there could be radiation pressure supported stars (RPSSs) even in Newtonian gravity. Much later, Mitra found that one could also…”
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