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  • so really, really fascinating.

  • Excellent paper published about a week ago.

  • Now in science, many would consider the most prestigious journal Long's Like nature thistles.

  • Beautiful, beautiful, staggering work.

  • The paper is about basically pushing the limits off our ability to manipulate magnets, going all the way down to single out of magnets, basically on dhe spin that was put on this in the in the media was that basically, they've reduced the amount of storage we need for our single magnetic bit from about a 1,000,000 atoms, roughly down to 12 atoms.

  • But it's so much more than that, it's, you know, you can put that the sort of technological spin on it.

  • But importantly, this work was done not only at liquid helium temperatures.

  • Four point to Calvin actually, don't half a Calvin 500 milli Calvin.

  • That's unbelievably cold on also in on ultrahigh vacuum.

  • So this is not gonna come to a computer thio iPod or DVD player or whatever to you anytime soon.

  • Forget about all that what it is.

  • It's just beautiful, fundamental science.

  • So what they've done is they've taken little arrears of atoms.

  • Move them.

  • I will iron atoms.

  • They've moved them around on.

  • These atoms are like basically atomic scale magnets.

  • They have a spin right.

  • We'll have to get into the very tricky area off spin on magnetism.

  • But before I do that, let's let's use a sort of these are really, really fun.

  • If you have got these going to get something called the Weather near Denny, near Dinu magnets on dhe, they are really, really quite cool.

  • You see that one just clicked into former Ring, but it ends together.

  • Let's get to on the terrible.

  • Let's get another to hear.

  • So let's bring this and you know how much fun it is to play with magnets.

  • But these are pretty strong magnets, so you can see it's reacting already.

  • Drag it up, move it around, open hopes similarly, comported under here moving around.

  • So I'm just putting the magnets under the table.

  • The magnetic field can travel through the word of the terrible, but you can.

  • You can build up little structures.

  • You can build up a wide range of different things with these.

  • Why does this link into the paper?

  • The reason this links into the paper as well.

  • What?

  • Well, well, how magnets work.

  • There was that classic song that line in that classic song by insane clown posse, If I remember correctly, Key thing is that you get a magnetic field when you're removing charge on dhe.

  • Let's think about the smallest moving charge you can have, which is to take the electron.

  • And so the electron has it acts like a tiny little magnet.

  • We see it's got its its its magnetic moment, and it can interact with order electrons who are also tiny little magnets and you got a north side pole and they can interact.

  • But we call that counts that physicists call that spin we call that electron spin.

  • And the reason was is that back in the early days of quantum mechanics were trying to find wears off connecting these really weird properties that happened all the way down in the atomic molecular level with something that we could get our heads around in the real world.

  • And so the idea was, Well, okay, maybe the electron is like a little ball of charge, and it spins around.

  • I'm not spinning round gives rise to this because you got a circulating charge gives rise to ah, magnetic moment and you get a tiny little magnet.

  • Problem is, is that if you calculate just the rate of spin you need, it's an excess of the speed of light.

  • Doesn't quite work.

  • Physicists.

  • We get this idea, and I think we no longer will.

  • We call it spin.

  • I don't think very many physicists who work in this area really think of it as a spinning electrons.

  • You busy Think of it as a property, and you almost certainly the model I have in my head.

  • Where's my marker?

  • I've done one before.

  • Is that basically one electron your little born?

  • It's got It's labeled with a spin on.

  • It could be spin up or could be spend down on Those can interact.

  • You have little interacting magnets, and that's really why you can take a fridge magnet and put it on your door.

  • It's because all those electrons collectively act together, build up a big magnetic field basically, and that allows you thio, put your fridge magnet on your door or similarly allows you to do fun things like this.

  • You can see that that's a rather strong force, but all it's the reason it comes about issue to the interactions of electrons.

  • What these guys did was to take individual iron atoms, and I own, as you know, was magnetic.

  • And the reason it's magnetic is because it has impaired electrons.

  • So in reason so many materials aren't magnetic is that you have the electrons pair up.

  • So you got one magnet like that one minor point don't got north side so north, and they cancel each other.

  • Right?

  • Iron has impaired electrons, which means it acts as a little nature.

  • Outta Max is a little magnet, so what they've done is they've taken individual atomic magnets they've moved them together on.

  • They've measured using something called a scanning tunneling microscope.

  • They've measured basically the magnetic field.

  • They've measured the magnetic interaction between the tip on the atom at the surface.

  • What's remarkable is going beyond atomic manipulation.

  • Other groups have done this before, but not quite a thing.

  • This scene where the key thing is that not only can they see the individual magnets at the atomic level, they can flip them.

  • That can change them on bacon, see also as they increase the temperature, how these magnetic demeans move around on, they can work out just how small.

  • You knew a set of atoms.

  • You need tohave a stable magnetic bit.

  • Because what happens is that it?

  • You warm things up.

  • Andi make things smaller.

  • The problem is that fluctuations tiny, tiny little changes in the environment can influence those magnetic spins on can wash out that magnetic information.

  • What is so impressive about this is that Theo IBM mantra is think so.

  • What they've done here is we've been cold it in binary thes later's t hit I en que Onda.

  • As you can see, each one of these blobs is an individual.

  • Artem, basically on the blue ones are where the I can't remember which way around it is.

  • But the blue ones aware that spin the little magnet points this way on.

  • The white ones are where the magna points that way, and they can flip these that conflict these individual atomic magnets.

  • So anatomy is one of these blobs, basically.

  • So that's where they've been called the gonorrhea thes atoms.

  • And what they've done is they've been cold it 01010011 So what?

  • These are the difference in the red and the blue is the spin, said whether it spins up with Spin zone or whether magnets pointing north so that we're not So So my computer over there on your computer at home, the way you store information on the hard disk is you exploit these magnetic interactions, these magnetic forces.

  • But you do it with millions and millions and millions of atoms.

  • What these guys have done is that I've scaled it all the way down.

  • They've looked at the fundamental limits.

  • How small can we make a magnetic bit arm or they've gone beyond that.

  • They've looked at what he does temperature affect this.

  • They've looked at Well, if we put the atoms in this pattern, so they're they're stacked up nice and evenly.

  • Does that give us a stronger magnetic interactions?

  • Does that preserve the deer tomb or or if we sort of staggered them a little bit?

  • What I really like about the IBM work is that it's always so elegant.

  • You read the paper and you go, you got thrown out of the doughnut and questions arise on you go all right.

  • They don't not as well.

  • And then you think maybe on then every single question you can think of is in there, and it's just years and years of work, and it's just, really, really comprehensive, really elegant.

  • And that's why the papers always end up in science and nature because they are setting the bar.

  • How difficult is it?

  • It's unbelievably difficult.

  • You have to get your tip in the right magnetic state you're working out in this case, not just the temperatures of a few.

  • Calvin.

  • You're working at hundreds of Millie Calvin temperature you work in a pressure is comparable to that you find in deep space very, very tricky.

  • Very, very complicated, but so much fun.

so really, really fascinating.

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B2 中高級

世界上最小的磁性字節 - 60個符號 (World's Smallest Magnetic Byte - Sixty Symbols)

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    林宜悉 發佈於 2021 年 01 月 14 日
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