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[wierd]

The use of laser energy as the heating source might also have an effect on bond angle energies, and resulting topologies of crystals produced.

Enquiring mind wants to know, does the laser energy frequency matter? EG, do they need a CO2 UV laser, or would a visible light laser of comparable energy have the same results?

The 1atm pressure at room temperature from a coating of amorphous carbon suggests that this could be done at home using a candle (to apply amorphous carbon soot), some form of substrate (perhaps aluminium foil?) and a suitable laser light source (like a "burning" laser pointer, or a laser created using a dvd burner's laser diode.)

Creating "magnetic paper" out of carbon paper is also a potential DIY home project, assuming we dont need a special laser source.

[Eagleon]

APL Materials, the journal they published with, is open access. I think it kind of says something that I didn't even bother to check. edit: derf, hyperlinked in the middle, but here it is again
http://scitation.aip.org/content/aip/journal/aplmater/3/10/10.1063/1.4932622

Anyway. If you can get your dvd laser to pulse at 20 ns, you probably have the knowledge necessary to repeat this, if not the equipment necessary to determine whether anything happened at all DVD might be too large - 650, and 405 for blu-ray. They're using 193 nm ArK excimer, similar as they said to Lasik equipment.

[wierd]

The bigger concern is likely the "quaity" of the laser light.  Diode lasers are typically multimode emitters, where as good quality lab lasers are genuinely single mode.

Since the laser is just being used to flash heat the carbon (according to the press release anyway) then as long as your pulse length is right, you should be able to produce some limited quantity of Q-carbon with an inferior laser. (Which should be pretty easy to test for, since the Q-Carbon has a unique fluorescent profile.)

I dont know if you can drive a DVD laser at 20ns pulse though. It might be possible with some of those really high speed DVD drives though.

[redwallzyl]

  interesting. didn't think that would happen this soon. i for one welcome out new mutant overloads!

https://www.sciencenews.org/article/human-gene-editing-gets-green-light?tgt=nr

http://www.npr.org/sections/health-shots/2015/12/03/458212497/scientists-debate-how-far-to-go-in-editing-human-genes

[Furtuka]

http://factor-tech.com/connected-world/21062-a-fundamental-quantum-physics-problem-has-been-proved-unsolvable/

[TheBiggerFish]

Whooooooa.

[PTTG??]

So THAT's how the EM drive works!

kidding.

I'm afraid I don't quite understand the the concept- is this really saying that it's impossible to model spectral gaps? Does that mean there's no relationship between superconductivity and the other properties of a material?

[MetalSlimeHunt]

In other science news, apparently the D-Wave people published a practical demonstration showing that the D-Wave is a real quantum computer, not a conventional computer simulating quantum phenomena. Impressive, if accurate.

[PTTG??]

They described a grid of sites where the spectral gap is uncomputable as you let its size approach infinity. There is no known physical material that can exist with an uncomputable spectral gap in the real world, and that hasn't changed with this paper.

This does have important implications in physics though. When extrapolating macroscopic properties from microscopic ones, physicists like to take the limit as things go to infinity; e.g. start with Newtonian collisions of particles, take the limit as number of particles per volume goes to infinity, and you get fluid dynamics (more or less, I don't know all the details). This often makes things simpler; you would much rather analyze the Navier-Stokes equations than have to care about every single particle.

This paper shows, (for the first time?), that this method doesn't always work. We can't get any simple theory about the spectral gap of materials by taking the limit to infinity. It means there are materials out there where there is no simple answer in describing their spectral gap. Like OP's article said, it could depend on each individual atom.

I'll have to see if D-wave published in the same journal that revealed the health benefits of smoking a while back...

[Starver]

http://factor-tech.com/connected-world/21062-a-fundamental-quantum-physics-problem-has-been-proved-unsolvable/

...then we need to hack upwards into ToadyZero's raws and find out which pre-defined materials the [QUANTUMGAP] tag has been manually added to, obviously!

[Gigaz]

About the spectral gap paper: It is basically impossible that a quantum system can solve an undecideable problem, so this is probably not the point.

So either something is missing in the description of the problem, which would basically mean Quantum mechanics is incomplete. Or, more likely, the problem arises due to the infinite size of the system. This is not entirely physical, but an extremely common assumption for many problems. The paper basically predicts that there can be a material where you take a one kilogram block and it's an insulator, but a two kilogram block would be a conducting metal. So this is in some sense an awkward result. People can't solve realistically big quantum systems and if some quantum systems exhibit a phase transition (from gapped to gapless) at some arbitrarily large system size, there is really no way to compute that.

[Starver]

I'm starting to see possible parallels with Penrose Tilings.  They may be self-similar (patterns at one scale re-occur at larger scales), but when dealing with distance-sensitive stuff such as underlies the quantum world that could make (or break!) the existence of energy gaps in the substance.  As could the 'quantum solution' of different sub-sections of the same quasi-crystal whole.

Thus you could have a 'homogeneous' mass of material that does/does not exhibit the behaviour you want.  Cleave it in two (without 'damaging' it, except for the cleave-line) and the two apparently similar sub-masses are entirely unalike in whether they do/do not, themselves, exhibit the behaviour.

And all the above masses are finite, so can be solved for whether they have the spectral gap, or not.  It just remains insolvable as to whether the theoretically-infinite super-mass (i.e. not just limited to the original mass) has such a quality or not.

And of course there are far simpler constructs that we can say do or do not exhibit it, at any practical size or scale.  The problem is generalising to all possible (i.e. counting somewhere in the high Alephs of theoretical combinations) substances, that would remove the need for experimental assessment of a wide-range of generalised compounds and leave us with the possibility of plugging "I want this, given these constraints" into the formula and getting a range of possible answers out of it that we can then experimentally assess to confirm our complicated mathematics...

Or I might have the wrong end of the wrong stick.  I probably need to go read the original article properly, first.

[Helgoland]

Wendelstein 7-X is now operational! Another big step forward for fusion research!

[Dutrius]

Wendelstein 7-X is now operational! Another big step forward for fusion research!

That reminds me. A long time ago, I somehow came into the possession of a science annual type book from 1963.

Among the articles is one titled "Power For Tomorrow", concerning fusion power. It basically says that viable fusion power is not quite there yet, but we'll crack it soon.

More than 50 years later, we're still not quite there yet. But we'll crack it soon.

[wierd]

We WOULD have cracked it MUCH MUCH sooner, had spending been at levels other than "Oh, just give them a pittance to shut them up. We cant afford to unseat Big Oil right now." and more at "Oh, yeah-- We kinda need to actually consider having a replacement ready when we run out of carbon to dig up, huh?" levels.