Hi Christian,
Great essay! It is a nice overview of normal modes. Check out my essay and in particular equations 7 through 8. I derive the states of quantum gravitons associated with quantum hair on black hole coalescence as Hermite polynomials. This is an approximation, where the full solution is far more difficult and complex. However, this overlaps with the normal modes model. If you want more details I have attached to my first comment a mathematical supplement. Your work here is a path along these lines as I see it.
There should by one means or the other a way of looking at the quantum transition of a black hole to a black hole plus radiation quanta or particle as sharing basic features seen in how a hydrogen atom emits photons. I do think that quantum information is conserved, but I agree with the Hawking idea that it is in a form that appears concealed or unavailable to everyone but an observer capable of the most complete possible set of measurements.
I see you got slammed down right away. Welcome to FQXI essay contest. Here there is a whole avalanche of papers that are pure balderdash, and some of them are near the top voting ranks. This happens every time.
In this work I was motivated by Maryam Mirzakhani's death. She died of breast cancer last July, and the news for various reason made me angry. I had read one of her paper's back in 2014 when she won the Fields medal, and at the time I thought this had something maybe to do with physics. Last spring I studied the Ryu-Takayanagi (RT) formula and for some reason the day I heard of Maryam's death the insight on how her work connects with this hit me.
There is this problem with how gravitation and quantum mechanics merge or function in a single system. It is often said we understand nothing of quantum gravity, and this is not quite so. Even with the based canonical quantization of gravity from the 1970s in a weak limit is computable and tells you something. This theoretical understanding is very limited and big open questions remain. Of course since then far more progress has been made. The AdS/CFT correspondence, the Raamsdonk equivalence between entanglement and spacetime and the RT formula are some of the more recent developments. These indicate how spacetime physics has a correspondence or maybe equivalency with quantum mechanics or quantum Yang-Mills fields. However, an obstruction exists that appears very stubborn.
The vacuum is filled with virtual pairs of fields. With a black hole the gravity field causes one of these pairs to fall into the black hole and the other to escape. This means the quantum particle or photon that escapes as Hawking radiation is entangled with the pair that falls into the black hole, and so this means Hawking radiation is entangled with the black hole. So at first blush there seems to be no problem. However, if we think of a thermal cavity heated to high temperature photons that escape are entangled with quantum states of atoms composing the cavity. Once the entanglement entropy reaches a maximum at half the energy released the subsequent photons released are entangled with prior photons released. This would hold with black holes as well, but because of the virtual pair nature of this radiation it means Hawking radiation previously emitted in a bipartite entanglement are now entangled not just with the black hole, but with more recently emitted radiation as well. This means a bipartite entanglement is transformed into a tripartite entanglement. Such transformations are not permitted by quantum unitary evolution. This is called quantum monogamy requirement, and what this suggests is unitarity fails. To prevent the failure of quantum mechanics some proposed a firewall that violates the equivalency principle. This is called a firewall.
The firewall occurs when half the possible radiation is emitted, which is also the Page time. This also corresponds to the failure of a quantum error correction code. Error correction codes involve some deep mathematics; it is connected with the RT formula and I illustrate in my essay the connection with Mirzakhani's mathematics on the geodesics in hyperbolic spaces. Error correction is also tied with the packing of spheres or how oranges stack at the grocery store, the Kepler problem. This gets into the guts of what my paper is about. However focusing in an error correction corrects the mixing of information. Think of a library, in particular an elementary school library with little kids, and the patrons scramble up the order of books. The distance a books ends up from its right position is the Hamming distance. As the library gets mixed up an algorithm can manage this disordering. However, at about half mixing up things break down. The librarian has to virtually start over.
The solution with Susskind and others is to say spacetime variables and quantum states are equivalent. I do not disagree completely, but I think this is a complementarity instead of an equivalency. It means with either spacetime or quantum states you can account for the system, but at the expense of abandoning a description of the system by the other. You can't describe quantum gravity completely by both in the same measurement description. So this is a sort of Heisenberg uncertainty, if you will.
Cheers LC
