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Abhas Mitra is a noted Indianastrophysicist and is known for his trait of novel thinking on several frontline astrophysics problems. He is the first astrophysicist to suggest that photo-meson process rather than proton-proton collision process could be the leading mechanism for Ultra High Energy gamma-ray production in ultra-compact X-ray binaries. As far as India based astrophysicists are concerned, he was the first to carry out research on various theoretical aspects of modern Gamma Ray Burst paradigm,,. In particular, it was he who first pointed out that the so-called Fireball model may not work unless the presence of an ambient magnetic field, much stronger than the typical interstellar value, would be assumed. Accordingly, he was the first astrophysicist, based in India, who got an oral slot for presentation on the `Theory and Models' of cosmic gamma ray bursts in a prestigious international scientific conference.
One of his recent papers claims to contain an exact mathematical proof that the true/exact Schwarschild Black Holes have zero gravitational mass:. This paper claims that no objects with a finite gravitational mass can be true/exact black holes. If so, the so-called Black Hole candidates cannot be true black holes even though they may resemble `black holes' in many respects.
Recently, Mitra and Norman Glendenning have shown that continued gravitational collapse of massive objects should result in a radiation pressure supported quasi-static hot ball of plasma rather than a true black hole. Such a quasi-static self-gravitating hot ball of plasma has been termed as `Eternally Collapsing Object' in view of the fact it is ever shrinking to asymptotically attain the true Schwarzschild black hole state having M=0.
Relativistic astrophysicists have struggled for ages to find an exact general relativistic counterpart of the Newtonian Virial theorem : for a quasi-spherical system. And Mitra found such an exact GR version of Virial Theorem in 2006.
Similarly, it has generally been believed that inclusion of fluid pressure increases the Active Gravitational Mass Density in general relativity. However, he has shown that pressure eventually decreases the same and pressure gradient indeed opposes gravitational collapse.
The total energy of the universe, inclusive of matter, radiation and gravitation in the Big Bang has been worked out by Mitra by directly using Einstein's original prescription (i.e., without using any super-potential). This maiden direct computation claims to show that the principle of energy conservation is indeed violated in the Big- Bang model. And only way the principle of energy conservation would be valid here would be if the model would degenerate into a Newtonian one with zero mean matter density!
He has introduced a new astrophysical term - `Einstein - Eddington Time Scale' in the honor of Albert Einstein and Arthur Stanley Eddington. This time scale is based on the fact that in the context of General Relativity, the total available energy of an object in the rest frame of a distant observer is :, and the maximum rate at which this energy can be radiated out is given by the general relativistic Eddington luminosity. The relevant paper where this concept got developed was selected as one of the highlight publications of Max Planck Society.
Apart from astrophysics, his interest in physics ranges from Classical Mechanics to Quantum Computing.