“If quantum gravity in a flat space allows for a holographic description by a standard quantum theory, then there must by physical quantities, which can be calculated in both theories — and the results must agree,” says Grumiller. Especially one key feature of quantum mechanics -quantum entanglement — has to appear in the gravitational theory.
When quantum particles are entangled, they cannot be described individually. They form a single quantum object, even if they are located far apart. There is a measure for the amount of entanglement in a quantum system, called “entropy of entanglement.” Together with Arjun Bagchi, Rudranil Basu and Max Riegler, Daniel Grumiller managed to show that this entropy of entanglement takes the same value in flat quantum gravity and in a low dimension quantum field theory.
“This calculation affirms our assumption that the holographic principle can also be realized in flat spaces. It is evidence for the validity of this correspondence in our universe,” says Max Riegler (TU Wien). “The fact that we can even talk about quantum information and entropy of entanglement in a theory of gravity is astounding in itself, and would hardly have been imaginable only a few years back. That we are now able to use this as a tool to test the validity of the holographic principle, and that this test works out, is quite remarkable,” says Daniel Grumiller.
This however, does not yet prove that we are indeed living in a hologram — but apparently there is growing evidence for the validity of the correspondence principle in our own universe.
So we are not living in a hologram, so far as we know.
By the way, a hologram of what? Exactly?
Here’s the abstract:
We present the analytical calculation of entanglement entropy for a class of two-dimensional field theories governed by the symmetries of the Galilean conformal algebra, thus providing a rare example of such an exact computation. These field theories are the putative holographic duals to theories of gravity in three-dimensional asymptotically flat spacetimes. We provide a check of our field theory answers by an analysis of geodesics. We also exploit the Chern-Simons formulation of three-dimensional gravity and adapt recent proposals of calculating entanglement entropy by Wilson lines in this context to find an independent confirmation of our results from holography. (paywall) – Arjun Bagchi, Rudranil Basu, Daniel Grumiller, Max Riegler. Entanglement Entropy in Galilean Conformal Field Theories and Flat Holography. Physical Review Letters, 2015; 114 (11) DOI: 10.1103/PhysRevLett.114.111602
There is so much better evidence for fine-tuning than for the universe as a hologram, yet this stuff gets the ink and fine tuning is on the DISPROVE! list. Ever wonder why?
See also: The multiverse: Where everything turns out to be true, except philosophy and religion
But who needs reality-based thinking anyway? Not the new cosmologists
Multiverse cosmology: Assuming that evidence still matters, what does it say?
In search of a road to reality
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