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Twisted graphene has become the big thing in physics

quantamagazine.org

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Re: Twisted graphene has become the big thing in physics

#31

Post by aspaceman »

keyle wrote: post #5

Pardon my interruption but I searched for 'use' or 'usage' and came up empty. Anyone can tell a regular guy why it's a big deal and what are the applications? ta

>>> The stakes in the race to come up with easier to make, better performing, higher-temperature superconductors are huge. Aside from the oft-evoked vision of levitating trains, reducing the energy loss in electric power transmission would boost economies and sharply cut harmful emissions around the world. Qubit fabrication could suddenly become practical, perhaps ushering in the rise of quantum computers. Even without superconductivity, ordinary computers and other electronics could get a huge boost in performance versus cost from twistronics, due to the fact that entire complex electronic circuits could in theory be built into a few sheets of pure carbon, without needing a dozen or more complexly etched layers of challenging materials common to today’s chips. “You could integrate wildly different properties of matter into these circuits right next to one another, and vary them with local electric fields,” said Dean. “I can’t find words to describe how profound that is. I’d have to make something up. Maybe dynamic material engineering?” >>>

Re: Twisted graphene has become the big thing in physics

#34

Post by soulofmischief »

rubyn00bie wrote: post #19
soulofmischief wrote: post #15

Earlier quoted context omitted.

No, because that would violate the Law of Conservation of Energy, which according to our current understanding would imply that this form of "perpetual motion" is impossible as long as the system experiences some sort of load. [0] [0] https://en.wikipedia.org/wiki/Conservation_of_energy

I don’t think I’m talking about perpetual motion at all... When I say never loses a charge I don’t mean it’s limitless capacity. I mean it could be charged 1,000,000 times without any affect on the capacity of the system? Maybe a better way to say it, a battery that does not degrade with each use. Superconductors allow for the perfect transfer of electrons without any loss? So like if I had a giant earth sized graphe…

Ok I see, by "not losing its charge" you meant not wearing down from repeated use. Technically speaking the charge would be the amount of electrical potential energy stored in the device.

This system is still subject to the laws of thermodynamics, however.

AFAIK ideal superconductivity does not exist outside of theoretical physics, just as ideal platonic solids do not exist in the real world. Things get bumpy close up, and then they get fuzzy.

Even if you could maintain a "perfect loop" of electrons along a wire, perfectly insulated from outside forces including EMI and gravity, any observation of the system would still introduce entropy from the outside world and eventually degrade the system unless it is self-correcting.

An ambient self-correcting conductor would be a massive breakthrough.

Re: Twisted graphene has become the big thing in physics

#35

Post by peanutz454 »

mailslot wrote: post #17
gigatexal wrote: post #8

Yes. There’s not applicable commercially viable things based on graphene yet. But superconductivity will be a revolution in many ways and especially in computing.

Superconductivity would revolutionize transportation, low cost medical imaging with MRIs, and weapons. Lots of weapons.

I understand what superconductivity is and how it can revolutionize things in general. But why those things in particular? So transport for example - better maglev trains?

Re: Twisted graphene has become the big thing in physics

#36

Post by ouid »

Arbalest wrote: post #29
ouid wrote: post #26

Earlier quoted context omitted.

I'm definitely not an expert, but just because you need force to go around corners doesn't mean you need work. An unchanging magnetic field in fact exactly accomplishes this, as it always accelerates an electron perpendicular to its motion, thereby leaving the energy of the electron unchanged.

That sounds a lot like a slingshot maneuver around a planet to get more momentum. Strictly speaking you're taking energy from the planet/sun to do so. An unchanging magnetic field still exists in the real universe, and I find it difficult to believe that it would be completely unaffected by the interaction. fwiw I'm also no expert edit: I'm taking unchanging to be a practical implementation of say a permanent magnet…

no, what I'm talking about is more like a perfectly circular orbit around the sun, where the direction of the acceleration is always exactly perpendicular to the motion.

Re: Twisted graphene has become the big thing in physics

#37

Post by intenex »

Fairly shocking to me that Yuan Cao received literally a single glancing mention here, but he was clearly the one who actually made the pivotal discovery, and is the first author on the Nature paper (https://www.nature.com/articles/nature26154), and was the one named to the Nature 10 in 2018 for his discovery.

Really mind boggling that this entire piece focuses all the attention on his supervisor and almost neglects to mention him at all.

Re: Twisted graphene has become the big thing in physics

#39

Post by PakG1 »

intenex wrote: post #37

Fairly shocking to me that Yuan Cao received literally a single glancing mention here, but he was clearly the one who actually made the pivotal discovery, and is the first author on the Nature paper ( https://www.nature.com/articles/nature26154 ), and was the one named to the Nature 10 in 2018 for his discovery. Really mind boggling that this entire piece focuses all the attention on his supervisor and almost neglect…

Cynical me asks isn't that how it works for PhD students?

Re: Twisted graphene has become the big thing in physics

#40

Post by Yuioup »

Vekz wrote: post #30
Yuioup wrote: post #25

Earlier quoted context omitted.

So how is that coming along. It seems like I've been hearing about graphene for ages now.

Define 'ages'

Ever since the physicist got a Nobel prize for it. I don't remember who it was and when it happened (I'm too lazy to Google it right now).
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