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Black hole hologram appears in a graphene flake
Much research on black holes is theoretical since it is difficult to make actual measurements on real black holes. Such experiments also need to be undertaken over decades or longer. Physicists are therefore keen to create laboratory systems that are analogous to these cosmic entities. New theoretical calculations by a team in Canada, the US, UK and Israel have now revealed that a material as simple as a graphene flake with an irregular boundary subjected to an intense external magnetic field can be used to create a quantum hologram that faithfully reproduces some of the signature characteristics of a black hole. This is because the electrons in the carbon material behave according to the Sachdev-Ye-Kitaev model.
[...] [Marcel Franz:] "This model is an illustration of a type of 'holographic duality' in which a lower-dimensional system can be represented by a higher dimensional one. In our calculations, the former is N graphene electrons in (0+1) dimensions and the latter the dilation gravity of a black hole in (1+1) dimensional anti-de Sitter (AdS2) space."
Remarkably, this model accurately describes the physical characteristics of black holes for large values of N (larger than 100 ideally). These characteristics include non-zero residual entropy, and fast scrambling of quantum information at the black hole singularity (the region beyond which not even light can escape the tug of its gravity).
Quantum Holography in a Graphene Flake with an Irregular Boundary (DOI: 10.1103/PhysRevLett.121.036403) (DX)
(Score: 5, Interesting) by Anonymous Coward on Thursday August 02 2018, @07:09AM (1 child)
In English what this means is that graphene, with a particular edge configuration can, under intense magnetic fields, exhibit some properties similar to a black hole.
Consider that graphene is for all intents and purposes 1 dimensional, that is to say, it is a single layer of atoms.
So in a nutshell, if you take a single atom thick layer of carbon, break off its edge in a particular way and subject it to intense magnetic fields, it will do some, but not all of the things that blackholes are known to do.
The items listed are...
#1 Non-zero residual entropy. Entropy is a measure of the disorder of information in a system. Send information to it and it scrambles the information pretty perfectly.
#2 Fast scrambling of information at the singularity, but it incorrectly conflates the singularity with event horizon when it says (the region beyond which not even light can escape the tug of it's gravity).
Fast scrambling should be actually be called "instant" since it happens in roughly the planck time (smallest unit of time for which we can say a unit of time has passed).
So the two items are actually redundant. This could easily say...
We charged a layer graphene with a strong magnetic field and it scrambled / absorbed all the information sent at it instantly (as far as we are able to measure), this information then proceeded to stay scrambled when we removed the field, it did not spontaneously re-order.
I'm deeply disturbed by the fact that they conflate singularity with event horizon. In a black hole the scrambling occurs at the singularity and for blackholes with a large enough event horizon, the event horizon is usually crossed with nothing remarkable being noticed by whatever crossed.
Yet at the event horizon, time starts to become a space like dimension, meaning it leads to a single point inexorably. Space also becomes timelike, you can only move forward, you cannot move backwards. As you approach the singularity gravity intensifies and if it's spinning you'll be shredded by tidal gravity as though you had stepped into a blender. Either way, you are eventually strung out into atoms, the atoms are strung out into subatomic particles (how they get past the fact that separating quarks simply produces more quarks is beyond my ability to understand https://en.wikipedia.org/wiki/Gluon [wikipedia.org] ). Those particles are accelerated to light speed or extremely close to light speed, becoming more and more energetic as they race towards the singularity. Eventually from the point of view of the singularity, the information that was you is blue shifted to at least gamma rays and if space is not quantized, then they may go to energy levels beyond gamma rays, meaning gravity has reduced your wavelength to less than 1 planck unit in a sort of Achilles and the Tortoise paradox https://en.wikipedia.org/wiki/Zeno%27s_paradoxes#Achilles_and_the_tortoise [wikipedia.org] . No one can really say anything about what happens beyond that. A particle with a wavelength of 1 planck unit is the definition of "planck energy" which is the energy level of the universe at the big bang. Accelerating a particle to that level should result in a localized big bang, but another blackhole would likely form well before that.
I have a hunch (but not the math skills to prove it), that time comes to a stop somewhere for you; the gamma rays or whatever you have become, eventually tunneling out as hawking radiation, perhaps instantly or perhaps trillions of years later or maybe even in the past. Time gets a little weird inside of a black hole and time doesn't mean the same thing at all as it does here in relatively flat spacetime. Add to that the fact that your energy level is neigh infinite and also the fact that you are basically no longer particles, but a field of subatomic blackholes. Since entropy is perfect, it may in fact mean that whatever it is (gamma rays, subatomic blackholes etc) that represents what were once you, smear out across space and time in a perfectly even distribution, it seems obvious to me that you don't stay there forever, and likely never reach a "there". In truth there's probably not a "there" to reach.
In some ways the comment about using a shadow to determine properties of a 3d object is very correct. If a shadow has a round edge, you can be assured that the object casting the shadow has roundness that carries into at least 3 dimensions. In the same way, they are saying that information which crosses this boundary goes only inwards. This is impressive when you consider that information travels in waves and waves typically spread out from the point of transmission. This is saying the that in their experiment the entire wave instead concentrates towards the center of the 2d mass. Think about that for a moment. A "wave" of light is a probability distribution. For what they are describing to be truth, it means that in the presence of a magnetic field around a piece of carbon, the wave completely collapses and goes enters the horizon 100% of the time. That's highly improbable if true. I'm extremely curious to know what would happen if they sent an entangled pair, with one being directed at the horizon and one directed to a detector. Would the partner really just simply not arrive at the detector???
If they can find a way to shrink this down, it might be a very efficient way to create a laser, by oscillating the magnetic field enough to collimate the light waves, but not so much that it results in complete loss, of the wave function. So this may have practical applications, but it would depend on the strength of the magnetic field required. Another use would be to absorb radio waves, causing disruption of communications services. There are quantum encryption implications here as well that I am cannot quite put into words.
Another interesting thought while my mind is considering all of this...
Graphene being 2d carbon, might actually serve to be the straw that breaks the camel's back so to speak during collapse of a super nova. Effectively functioning as a seed material and making the difference between settling down as a neutron star or fully collapsing into a stellar remnant blackhole. If there is enough carbon blown off during the collapse, and considering the absolutely ludicrous magnetic fields around a young neutron star, it might work. There have been super novas recorded that were orders of magnitude more intense than thought possible, if the magnetized soot is doing interesting stuff at this scale, it might scale up as well.
(Score: 0) by Anonymous Coward on Thursday August 02 2018, @07:19AM
2 dimensional!!! Graphene is 2 dimensional. I can't believe I let that 1D statement slip through. Doh!