Calculations of Ahmed Almheir and colleagues are inspired by string theory but are claimed to stand on their own. From the popular article one learns that besides various calculational tricks, the calculation involves a lot of fashionable stuff: wormholes, the holographic principle, emergent space-time, quantum entanglement, quantum computers. To my opinion, the calculation is a model for BHe evaporation rather than a real calculation starting from basic principles for the simple reason that no quantum theory of gravity exists.
The calculation is not able to tell exactly how the information leaks out from the blackhole, which would eventually shrink to a point. The entanglement entropy of BH with radiation would start from zero and increase and eventually return to zero as BH has disappeared.
From the beginning it has been clear that BHs represent the failure of general relativity. This was also clear for Einstein. Then came the theoreticians who believe that all problems - also those which would requirea profound modification of basic postulates - can be solved by computing. Then they compute and compute and .... and eventually proudly declare "Problem solved". Here is an excellent example of this phenomenon. Einstein would have asked what goes wrong with general relativity and developed a better theory. I choose the same approach: TGD leads also to a profound modification of quantum theory itself.
In TGD framework a new ontology of quantum theory - I call it zero energy ontology (ZEO) - predicts that ordinary ("big") state function reductions (BSFRs) change the arrow of time. There is a direct empirical and experimental evidence for this (experiments of Minev et al) and the new view leads to a general theory of self-organization, quantum criticality and self-organized quantum criticality (see this). For understanding of life this vision is especially relevant.
Number theoretic vision about TGD predicts also a hierarchy heff=n×h0 of Planck constants and phases with large value of heff corresponding to dark matter. Therefore BSFRs occur in all scales and imply that physics looks for a standard observer classical in all scales although BSFRs are discontinuous they look like continuous deterministic time evolutions (their superpositions, to be precise) leading to the final state of BSFR. There would therefore no limit at which quantum mystically transforms to classical. Also the basic paradox of quantum measurement theory is solved.
The postulated unitary evolution of BH would be replaced by a sequence of unitary evolutions followed by TGD analogs of "weak" measurements, "small" state function reductions (SSFRs). This replacement would hold true for the time evolution of any system. SSFRs would break the unitary evolution to unitary pieces. In TGD inspired theory of consciousness the sequence of SSFRs would define the life cycle of a conscious entity ending with BSFR- death or falling a sleep - followed by a "reincarnation" with an opposite arrow of time.
TGD provides also a detailed model for blackhole like objects as tangled magnetic flux tubes filling the volume (see this). BSFRs are possible also for the TGD counterparts of blackholes and indeed, when BH-like objects become very old they make BSFR and the evolution leading to BH ccurs in reversed time direction! For instance, quasars are excellent candidates for time reversals of these analogs of BH-like objects and also analogous to whiteholes (see this).
The calculation involves many notions appearing also in TGD.
- Holography (or rather, strong form of holography) follows from general coordinate invariance in TGD framework.
- AdS/CFT is replaced with strong holography meaning that data at 2-D surfaces code determine space-time surface and evolution of induced spinor fields. The representability of space-time as surface in either M^8 or M^4xCP_2 (M^8-H duality) is a new element and an essential piece of TGD. These alternative but equivalent choices of the imbedding space are unique from the condition that the twistor lift of TGD exists.
- Calculation involves also extremal surfaces which are minimal surfaces. In TGD framework space-time surfaces are preferred extremals satisfying infinite number additional conditions besides field equations. They are minimal surfaces which are also extremals of Kä:hler action. They contains as analogous of blackhole horizons light-like 3-surfaces at which the metric changes its signature from Minkowskian to Euclidian as 3-surfaces identifiable as carriers of quantum numbers of particles: the presence of Euclidian space-time regions identifiable as interiors of elementary particles is something totally new. There are also string world sheets and partonic 2-surfaces, which are also minimal surfaces.
- The analogs of blacholes themselves are magnetic flux tubes carrying monopole flux filling the entire volume. The quantized thickness of the flux tube characterizes these objects and ordinary blackholes are only a special case. There is not blackhole singularity.
For a summary of earlier postings see Latest progress in TGD.