Black holes are like a hologram

Another summary of a press release based on a study that doesn't seem to actually find anything new or 'surprising'. As the 'article' states, the holographic principle is an idea that is 30 years old.

As I understand it, this paper is novel because it has found a scenario, a set of rules, where the math shows that the universe could indeed work this way...but this particular set of rules doesn't seem to be the ones we see in this universe. (I'll get to the specifics in a moment)

Why is this still useful? Because it is a starting point, a model that confirms the theory is workable. If the result had been negative, then some parts of the theory could be ruled out.

Now to the specifics from the original paper's abstract:

> We study this issue in the context of gravity with a negative cosmological constant. We exploit the most basic example of the holographic description of gravity (AdS/CFT): type IIB string theory on AdS5×S5, equivalent to maximally supersymmetric Yang-Mills theory in four dimensions. We thus resolve a long-standing question: Does the four-dimensional N=4 SU(N) Super-Yang-Mills theory on S3 at large N contain enough states to account for the entropy of rotating electrically charged supersymmetric black holes in 5D anti–de Sitter space? Our answer is positive.

Lots of words. A few things to take away is that this paper talks about a universe with four spatial dimensions, not three, and it considers "anti-de Sitter space", which would be a universe that loops back on itself instead of being infinite and flat as our universe appears to be. Last thing is that because the rate of expansion of the universe is accelerating, the cosmological constant is probably greater than zero but this theory only considers a scenario where the cosmological constant is negative.

Fascinating subject but the information density of this article falls short of my event horizon.

> For scientists, black holes are a big question mark for many reasons.

The writing of this piece is so shockingly bad that I wonder if it was machine translated.

>"Yet, according to new research by scientists in Italy, black holes could be like a hologram, where all the information is amassed in a two-dimensional surface able to reproduce a three-dimensional image. In this way, these cosmic bodies, as affirmed by quantum theories, could be incredibly complex and concentrate an enormous amount of information inside themselves, as

the largest hard disk that exists in nature, in two dimensions."

Somewhat irrelevant question but is the holographic universe theory a reasonable hypothesis for the universe expanding at different rates in its life since that could be explained by new material falling into the black hole that the holographic universe lives on.

If the universe is a hologram (or sorts) then non-locality should be expected, and spooky action at a distance is not paradoxical or terribly interesting.

Black holes dont exists. Good try, anyway.