LQG has not been shown to violate the holographic principle

[ohwilleke]

Backreaction has the story: http://backreaction.blogspot.com/2015/09/no-loop-quantum-gravity-has-not-been.html debunking this article:
Violation of the Holographic Principle in the Loop Quantum Gravity
Ozan Sargın, Mir Faizal http://arxiv.org/abs/1509.00843

and also showing the authors behaving badly. From the blog post:

You might get away with the impression that we have here two unfortunate researchers who were confused about some terminology, and I’m being an ass for highlighting their mistakes. And you would be right, of course, they were confused, and I’m an ass. But let me add that after having read the paper I did contact the authors and explained that their statement that the LQG violates the Holographic Principle is wrong and does not follow from their calculation. After some back and forth, they agreed with me, but refused to change anything about their paper, claiming that it’s a matter of phrasing and in their opinion it’s all okay even though it might confuse some people. And so I am posting this explanation here because then it will show up as an arxiv trackback. Just to avoid that it confuses some people.

 

[marcus]

If you are interested in this general area, e.g. relating LQG to AdS/CFT, check out the 3rd quarter MIP poll.
https://www.physicsforums.com/threads/poll-third-quarter-2015-mip-most-important-qg-papers.835822/

Among other things it lists this interesting note by Norbert Bodendorfer, who did his PhD with Thiemann.

A note on quantum supergravity and AdS/CFT
Norbert Bodendorfer
(Submitted on 7 Sep 2015)
We note that the non-perturbative quantisation of supergravity as recently investigated using loop quantum gravity techniques provides an opportunity to probe an interesting sector of the AdS/CFT correspondence, which is usually not considered in conventional treatments. In particular, assuming a certain amount of convergence between the quantum supergravity sector of string theory and quantum supergravity constructed via loop quantum gravity techniques, we argue ...
...with the aim of serving as a starting point for a more in depth interaction between the string theory and loop quantum gravity communities.
8 pages

 

[Dr Faizal]

Backreaction has the story: http://backreaction.blogspot.com/2015/09/no-loop-quantum-gravity-has-not-been.html debunking this article:
Violation of the H
1] In this paper, they are not taking about t’ Hooft’s holographic bound but Yurtsever’s holographic bound. The t’ Hooft’s holographic bound is motivated from entropy of a black hole, and so in it the entropy scales as A. (ref [9]-[10]) However, the Yurtsever’s holographic bound is derived from local quantum field theory in flat spacetime, and in it the entropy scales as A^{3/4} (ref [28]-[31]). It is the Yurtsever’s holographic bound whose violation has been studied in this paper.

2] The area of the black hole is a integer multiple of the Planck area, and this can be argued even from usual black hole thermodynamics (ref [12] ), as it has been demonstrated that the area of the black hole increases by a Planck area when one bit of information crosses the horizon. This has also been demonstrated using the Wheeler-DeWitt approach (ref [34]-[35]). So, any the number of microstates cannot change by assuming discreteness, as the area of the black hole has a discrete spectrum even when no discreteness is assumed. However. polymer quantization does change the measure of the phase space, and this increase the Yurtsever’s holographic bound on the entropy.

All references are from the present version of the paper
Ozan Sargın, Mir Faizal http://arxiv.org/abs/1509.00843

Backreaction has the story: http://backreaction.blogspot.com/2015/09/no-loop-quantum-gravity-has-not-been.html debunking this article:
Violation of the Holographic Principle in the Loop Quantum Gravity
Ozan Sargın, Mir Faizal http://arxiv.org/abs/1509.00843

and also showing the authors behaving badly. From the blog post: