Lecture-4: The black hole information paradox. |Prof. Samir Mathur| 

Speaker: Prof. Samir Mathur, Department of Physics, The Ohio State University
Sathish Dhawan Visiting Chair Professor, CHEP, IISc, Bengaluru
Abstract:
In 1975, Stephen Hawking found a startling result: if black
holes have the structure deduced by Chandrasekhar, then quantum theory
will be violated. This result has been a crucial ingredient in the
search for a unified theory of physics for the past 40 years. Over the
past two decades, we have found a resolution to Hawking's paradox
through string theory. Black holes do not have all their mass in a
central singularity; instead they are horizon sized quantum objects
called fuzzballs. The large entropy of a black hole, called the
Bekenstein entropy, leads to a violation of the semiclassical dynamics
which had been assumed by Chandrasekhar. This resolution of the puzzle
has interesting implications for cosmology, which also manifests a
horizon at the cosmological scale.