What a truly insightful article; I'm particularly struck by how the unobservable strand fluctuations, despite their Planck radius, manege to so elegantly yield and imply general relativity, as Jacobson showed, while also realizing Verlinde's entropic gravity.
One is tempted to answer that strands deduce black hole entropy and temperature, which are quantum gravity effects and go beyond general relativity. However, these two effects have not been measured - and probably never will. (Though temperature T has been measured and confirmed in analog, sonic black holes.)
Worse, strands predict that no deviations from general relativity are big enough to be detected. No effects of space noise and space fluctuations, and no other effects of spatial non-continuity or fuzziness appear measurable.
In a sense, this is sad. Strands are a theory of quantum gravity, but they predict no new effects. Well, at least this explains why the search of the last 100 years did not bear fruit.
So the main advantage of strands is that one has the same model for black holes, for vacuum and for particles. It is a unified model, even though it predicts no new quantum gravity effects. Strands, of course, predict general relativity and complete particle physics, which at present, only one other model achieves, but they do not predict anything new beyond general relativity.
What a truly insightful article; I'm particularly struck by how the unobservable strand fluctuations, despite their Planck radius, manege to so elegantly yield and imply general relativity, as Jacobson showed, while also realizing Verlinde's entropic gravity.
An upcoming manuscript will also show how all of quantum theory arises, including wave functions. That will be additional fun.
One is tempted to answer that strands deduce black hole entropy and temperature, which are quantum gravity effects and go beyond general relativity. However, these two effects have not been measured - and probably never will. (Though temperature T has been measured and confirmed in analog, sonic black holes.)
Worse, strands predict that no deviations from general relativity are big enough to be detected. No effects of space noise and space fluctuations, and no other effects of spatial non-continuity or fuzziness appear measurable.
In a sense, this is sad. Strands are a theory of quantum gravity, but they predict no new effects. Well, at least this explains why the search of the last 100 years did not bear fruit.
So the main advantage of strands is that one has the same model for black holes, for vacuum and for particles. It is a unified model, even though it predicts no new quantum gravity effects. Strands, of course, predict general relativity and complete particle physics, which at present, only one other model achieves, but they do not predict anything new beyond general relativity.
Obviously, strands predict that all alternative theories to general relativity are not correct. (See also https://www.motionmountain.net/bet.html#detg )
In cosmology, however, two predictions differ from the usual story:
- Inflation did not occur.
- And, above all, the cosmological constant vanishes.