Physics

Prof. Manu Paranjape
Université de Montréal, Canada

Abstract:

Black holes admit quantum mechanical bound states of ultra light particles
such axions or neutrinos.  These states can undergo quantum transitions
absorbing or emitting gravitons.   Graviton trajectories, in the particle
picture, in principle can correspond to gravitons that orbit the black
hole arbitrarily many times before finally escaping to infinity.   Quantum
mechanically, such graviton trajectories correspond to graviton-black hole
scattering states which exhibit an arbitrarily large time delay before
they emerge at infinity.  The spontaneous emission of such graviton states
coupled with their subsequent stimulated emission as the graviton circles
around the black hole through the lasing medium, can in principle give
rise to significant amplification.  The observation of intense beams of
coherent gravitons would then be a confirmation of the existence of ultra
light massive particles and of the existence of black holes.  As the
coupling of gravitons to matter is so small, that trajectories of the
order of 10^30 m would be required for significant amplification. This
corresponds to 10^13 years.  It has only been at most 14 times 109 years
since the big bang.  Hence in some years particularly harmfully, amplified
graviton death rays will start to be emitted from black holes all over the
universe, they are in this sense a time bomb.  To be in the path of such a
ray will not be pleasant.