This book reviews a few different derivations of the Hawking radiation, most main solutions to the paradox proposed in the literature, and some analog laboratory experiments. A black hole is an object whose gravity is so strong that nothing, not even light, can escape its grasp. However, applying quantum field theory on a black hole background, Stephen Hawking showed that black holes are not completely black. In fact, they seem to emit a form of radiation that was named the Hawking radiation. The Hawking radiation appears to be thermal and in a quantum state that is independent of the initial state that formed the black hole; instead, it solely depends on the black hole's total mass, spin, and electric charge. A problem arises when we consider an initial system that collapses, forms a black hole, and eventually the black hole evaporates completely through Hawking radiation. Since Hawking radiation depends solely on the black hole's total mass, spin, and electric charge, it implies that numerous distinct initial states could all lead to the same final state. Consequently, the intricate details of the initial state seem to be lost, which contradicts the unitarity of evolution of closed systems, a fundamental principle of quantum mechanics. The unitarity principle implies that closed systems evolve in a reversible manner, such that, knowing a systems final state, and the way it evolved, one can always determine its initial state. The many-to-one evolution of the black hole initial state to radiation evolution is in a clear contradiction with this principle. This is the black hole information paradox. The black hole information paradox was found in the 1970s by Stephen Hawking. Over the past 50 years, it has attracted a lot of interest in the theoretical physics community and is still an active research field. Chapters are written by leading experts in the field.
1. Deriving the paradox: original derivation of Hawking radiation.-
2.
Alternative Derivations of Hawking Radiation.-
3. Is the information loss
problem a paradox?.-
4. Alternative theory for the quantum black hole
and the temperature of its quantum radiation.-
5. Paradox No More: How
Stimulated Emission of Radiation Preserves Information Absorbed by Black
Holes.
Ali Akil is Postdoctoral Research Fellow at the University of Hong Kong. He holds a Bachelors degree from the Lebanese University (2015), a Master of Science in Theoretical Physics from Durham University (2016), and a Masters degree in Graph Theory and Matrix Analysis from the Lebanese University (2017). He completed his Ph.D. jointly between the Hong Kong University of Science and Technology and SUSTech in 2023. His research focuses on the intersection of quantum information and gravity, with particular interests in the black hole information paradox, the bottom-up approach to quantum gravity, quantum reference frames, and dark matter physics. Beyond academia, Ali enjoys philosophy, politics, rock climbing, and music analysis and composition.
Cosimo Bambi is currently Xie Xide Junior Chair Professor at the Department of Physics at Fudan University. He received the Laurea degree from Florence University in 2003 and the Ph.D. degree from Ferrara University in 2007. He worked as a postdoctoral research scholar at Wayne State University, IPMU/the University of Tokyo, and LMU Munich. He joined Fudan University at the end of 2012 under the 1000 Young Talents Program. His research interests include black holes, X-ray astronomy, computational astrophysics, and tests of general relativity. He has published several books with Springer, either as author and editor.
