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Photonic Bell states creation around rotating black holes (arxiv.org)
52 points by ovidiu69 on Dec 8, 2016 | hide | past | favorite | 19 comments

I studied quantum information/foundations to research level, so may be able to give some input and obviate some of the wilder interpretations. This paper isn't directly in my field of interest (don't know much about relativity), so I'm happy to be corrected if I say something stupid.

You've probably heard that quantum information processing uses the "qubit" as an information primitive. A qubit is not itself a particle, but a "degree of freedom" which can be in one of a range of states. This degree of freedom could be spin, polarization, energy, and so on and so on. Unlike bits, a pair of qubits can be entangled, which means that their joint state is not decomposable into a statistical mixture of independent pairs of states.

The paper considers two degrees of freedom associated with photons emitted from the accretion disks of spinning black holes: polarization and orbital angular momentum (OAM). Essentially, there are two qubits per photon. After some reasonable assumptions and calculations we find that the two qubits are highly entangled; in fact, as entangled as it's possible for two qubits to be. The author speculates that may be able to detect this by measuring such photons with modern equipment. I suppose the motivation is that we might be able to use them for actual information processing tasks (although as far as I can see there's no benefit to this over preparing entangled qubits ourselves).

That's about it, I think. No time-travel, no communication, but a small point of interest.

I haven't read the paper yet (too much to do). But I wonder why it's posted in the "General Physics (physics.gen-ph)" category rather than under "General Relativity and Quantum Cosmology (gr-qc)" where most papers with similar topics are traditionally submitted.

The physics.gen-ph category on arXiv is a little odd, a little uncomfortable, and hard to describe. Here are a couple of quotes from discusions of arXiv moderation commenting on it:

"There is one middle option between acceptance and rejection: Dubious papers can be shunted to a category called “general physics,” or “gen-ph.” At best, gen-ph is a home for papers that don’t fit neatly into any other category; at worst, it is a crackpot dumping ground. Either way, it allows moderators to dodge the drama that comes with out-and-out rejections. For many authors, though, being relegated to gen-ph is just as galling as being rejected outright: As one such researcher told Reyes-Galindo, having his paper reclassified to gen-ph felt like a deliberate attempt to diminish the paper’s impact." -- http://oren365.tech/news/What-Counts-as-Science? (via Google cache)

"Personally, I have never had a problem with the arXiv moderation. I had a paper reclassified from gen-ph to gr-qc once by a well-meaning moderator, which is how I learned that gen-ph is the dump for borderline crackpottery. (How would I have known? I don’t read gen-ph. I was just assuming someone reads it.)" -- http://backreaction.blogspot.com/2016/05/the-holy-grail-of-c...

EDIT: I don't mean this as direct criticism of this paper, which might potentially be fantastic and just fit better in the general category for one reason or another than in gr-qc. (Or, some moderator might have been too harsh: entirely possible!) But I wanted to share some of the unspoken background information that many physicists would think about when seeing this link.

After you read the paper, will you share us your thoughts on it, please?!!

Something to note: More times than not, asking a liberal arts major about how quantum mechanics works is usually more valid and reputable than the preprint arXiv

You better had substantiate that claim.


It seems the very author of the paper on the arxiv posted the link here (ovidiu69 here, Ovidiu Racorean of the paper), and maybe he is willing to answer some specific questions?

Ovidiu, being a researcher, can you please tell what your scientific CV is, especially related to the topics of the paper?

I see you've submitted different papers to arxiv:


Have you had any interactions and/or reactions from the other researchers in the fields? Have you published somewhere else?

The stretch is that in the future blackhole state can be changed and send information back in time? Not seeing it.

Sorta worked in Interstellar, though perhaps not in the way you're describing. ;)

Are they suggesting black holes can be used as quantum computers?

Absolutely not. You could (if it's true, at a glance it's not terribly convincing) use this as a probe of curved-space QED (a very difficult field) or as a method to measure of the spin of black holes (currently done by different dark magic which isn't very reliable).

Something like that

Good idea for a science fiction story.

My thoughts too.

Perhaps they are talking to each other.. .

Edit -- You and I really are quite alike in thought sometimes. You must come and visit Southampton sometime now the house is a bit more sorted.

My thoughts too.

No, really! :)

This was ragingly interesting, but outside papers like these I wondered what the application of this at this stage might be; Great sci-fi could be had, was my conclusion.

!! I only just spotted this!

Oh man. Can we change this to https://arxiv.org/abs/1608.06822 ? This "write up" is very bad, and clearly comes from somebody who doesn't really grasp quantum mechanics, and the connection to QUESS is... not good, although this paper and that idea share certain buzzwords.


I should look at that

Wow. It has an austere and distant beauty, like whale calls.

I wonder what it means.

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