Quantum information paradox: Real or fictitious?

ABHAS MITRA

Theoretical Astrophysics Section, Bhabha Atomic Research Centre,

Mumbai 400 085, India

E-mail: amitra@barc.gov.in

Abstract. 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. Let us recall that quantum

mechanics (QM) demands an upper limit on the acceleration of a test

particle. On the other hand, it is pointed out here that, if a

Schwarzschild BH exists, the acceleration of the test particle

would {blow up at the event horizon in violation of QM}. Thus the

concept of an exact BH is in contradiction with QM and quantum

gravity (QG). It is also reminded that the mass of a BH actually

appears as an integration constant of Einstein equations. And it has

been shown that the value of this integration constant is actually

zero! Thus even classically, there cannot be finite mass BHs though

zero mass BH is allowed. It has been further shown that during

continued gravitational collapse, radiation emanating from the

contracting object gets trapped within it by the runaway

gravitational field. As a consequence, the contracting body attains

a quasi-static state where outward trapped radiation pressure gets

balanced by inward gravitational pull and the ideal classical BH

state is never formed in a finite proper time. In other words,

continued gravitational collapse results in an `eternally collapsing

object' which is a ball of hot plasma and which is asymptotically

approaching the true BH state with $M=0$ after radiating away its

entire mass energy. And if we include QM, this contraction must halt

at a radius suggested by the highest QM acceleration. In any case no

event horizon (EH) is ever formed and in reality, there is no

quantum information paradox.

Keywords. Quantum information paradox; black hole; eternally

collapsing object.

PACS Nos 03.67.-a; 04.20.Dw; 04.40.-b