Boaz Almog "levitates" a superconductor

772,929 views ・ 2012-07-02

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00:00
Translator: Morton Bast Reviewer: Thu-Huong Ha
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翻译人员: Yuan Chen 校对人员: Yuguo Zhang
00:25
The phenomenon you saw here for a brief moment
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你们在这里看到的这个短暂的现象是
00:29
is called quantum levitation and quantum locking.
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被称为量子悬浮和量子锁定。
00:35
And the object that was levitating here
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这个悬浮在这里的物体
00:39
is called a superconductor.
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被称为超导体。
00:41
Superconductivity is a quantum state of matter,
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超导是物质的一种量子状态,
00:47
and it occurs only below a certain critical temperature.
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只在特定的关键温度下发生。
00:51
Now, it's quite an old phenomenon;
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现在,这是一个比较老的现象了;
00:53
it was discovered 100 years ago.
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100年前被发现。
00:55
However, only recently,
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然而,就在最近,
00:57
due to several technological advancements,
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由于若干科技进步,
01:00
we are now able to demonstrate to you
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我们现在能够向你们展示
01:02
quantum levitation and quantum locking.
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量子悬浮和量子锁定。
01:06
So, a superconductor is defined by two properties.
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那么,超导体具备两种特性。
01:12
The first is zero electrical resistance,
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第一种特性是零电阻,
01:15
and the second is the expulsion of a magnetic field from the interior of the superconductor.
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第二种特性是从超导体的内部驱逐磁场。
01:22
That sounds complicated, right?
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这听起来有点复杂,是吗?
01:25
But what is electrical resistance?
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但什么是电阻呢?
01:28
So, electricity is the flow of electrons inside a material.
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那么,电就是物体内部的电子流。
01:34
And these electrons, while flowing,
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这些电子,当他们流动时,
01:38
they collide with the atoms, and in these collisions
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它们与原子相撞,在碰撞过程中
01:40
they lose a certain amount of energy.
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它们损失一定的能量。
01:42
And they dissipate this energy in the form of heat, and you know that effect.
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这种能量以热的形式消耗, 你们知道这种效果的。
01:48
However, inside a superconductor there are no collisions,
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然而,在超导体的内部,不存在这种碰撞,
01:54
so there is no energy dissipation.
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因此也就没有能量消耗。
01:59
It's quite remarkable. Think about it.
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想象一下,这是非常神奇的。
02:02
In classical physics, there is always some friction, some energy loss.
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在经典物理学中,摩擦和能量消耗是必然存在的,
02:07
But not here, because it is a quantum effect.
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但在这里并非如此。因为这是一种量子效应。
02:11
But that's not all, because superconductors don't like magnetic fields.
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但这不是全部。因为超导体不喜欢磁场。
02:19
So a superconductor will try to expel magnetic field from the inside,
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因此超导体会把磁场从内部驱逐出去,
02:24
and it has the means to do that by circulating currents.
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通过循环电流就能做到。
02:30
Now, the combination of both effects --
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现在,两种效应相结合--
02:33
the expulsion of magnetic fields and zero electrical resistance --
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驱逐磁场和零电阻--
02:39
is exactly a superconductor.
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就是超导体。
02:42
But the picture isn't always perfect, as we all know,
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但我们都知道,情况不总是那么完美的,
02:46
and sometimes strands of magnetic field remain inside the superconductor.
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有时候,有几束磁场会停留在超导体内部。
02:54
Now, under proper conditions, which we have here,
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现在,在特定的条件下,就像我们现在有的,
02:57
these strands of magnetic field can be trapped inside the superconductor.
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这些磁场束被困在超导体内。
03:02
And these strands of magnetic field inside the superconductor,
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这些超导体内部的磁场束,
03:09
they come in discrete quantities.
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它们以分散的数量进入。
03:12
Why? Because it is a quantum phenomenon. It's quantum physics.
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为什么?因为这是量子现象。 是量子物理学。
03:15
And it turns out that they behave like quantum particles.
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结果它们的运动就像是量子粒子的运动。
03:19
In this movie here, you can see how they flow one by one discretely.
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在这部短片里,你们能够看到它们一个个分散流动。
03:25
This is strands of magnetic field. These are not particles,
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这是磁场束。 不是粒子,
03:28
but they behave like particles.
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但它们的运动看起来像粒子。
03:33
So, this is why we call this effect quantum levitation and quantum locking.
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这就是为什么我们把这种效应称为量子悬浮和量子锁定。
03:37
But what happens to the superconductor when we put it inside a magnetic field?
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那么,当我们把超导体放入磁场内时, 它发生了什么变化呢?
03:43
Well, first there are strands of magnetic field left inside,
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首先呢,有几束磁场束会留在超导体里面,
03:48
but now the superconductor doesn't like them moving around,
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但现在超导体不喜欢让它们在周围移动,
03:52
because their movements dissipate energy,
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因为它们的运动会消耗能量,
03:55
which breaks the superconductivity state.
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这样会破坏超导体状态。
03:58
So what it actually does, it locks these strands,
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那么,它到底做什么了呢, 它锁定了这些磁场束,
04:02
which are called fluxons, and it locks these fluxons in place.
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这些磁场束被称为磁通量子, 它把这些磁通量子锁定在原地。
04:08
And by doing that, what it actually does is locking itself in place.
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如此一来,它就把自己给锁定在原位。
04:15
Why? Because any movement of the superconductor will change their place,
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为什么?因为任何超导体的移动都会改变它们的位置,
04:24
will change their configuration.
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改变它们的状态。
04:26
So we get quantum locking. And let me show you how this works.
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这样我们就得到了量子锁定。 让我向你们展示它是如何运作的。
04:31
I have here a superconductor, which I wrapped up so it'd stay cold long enough.
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这里,我有一个超导体, 我把它裹起来了,这样它就能保持足够长时间冰冷。
04:37
And when I place it on top of a regular magnet,
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当我把它放在一个普通磁铁的顶端,
04:41
it just stays locked in midair.
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它就被锁定在半空中。
04:45
(Applause)
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(鼓掌)
04:49
Now, this is not just levitation. It's not just repulsion.
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现在,这不仅仅是悬浮。 不仅仅是相斥。
04:53
I can rearrange the fluxons, and it will be locked in this new configuration.
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我能重置这些磁通量子, 它就能够被锁定在这个新的装置内。
04:58
Like this, or move it slightly to the right or to the left.
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就像这样,或者把它往左或往右稍微移动一下。
05:02
So, this is quantum locking -- actually locking -- three-dimensional locking of the superconductor.
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那么,这就是量子锁定--货真价实的锁定-- 超导体的三维锁定。
05:10
Of course, I can turn it upside down,
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当然,我也可以把它倒过来,
05:12
and it will remain locked.
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它还是会保持锁定。
05:15
Now, now that we understand that this so-called levitation is actually locking,
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现在,既然我们了解了这种所谓的悬浮其实是锁定,
05:24
Yeah, we understand that.
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是的,我们了解了这一点。
05:29
You won't be surprised to hear that if I take this circular magnet,
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如果我拿出这样一个环形磁铁, 你们就不会感到惊讶,
05:33
in which the magnetic field is the same all around,
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在这个环形磁铁里,各处的磁场是相同的,
05:37
the superconductor will be able to freely rotate around the axis of the magnet.
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超导体能够绕着磁铁的轴线自由旋转。
05:43
Why? Because as long as it rotates, the locking is maintained.
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为什么? 因为只要它在旋转,锁定就能够被保持下去。
05:49
You see? I can adjust and I can rotate the superconductor.
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看到了吗?我能调整 我能旋转这个超导体。
05:55
We have frictionless motion. It is still levitating, but can move freely all around.
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我们有了无摩擦运动。 它仍然在悬浮,但能够自由移动。
06:01
So, we have quantum locking and we can levitate it on top of this magnet.
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因此,我们有了量子锁定 并且我们能把它悬浮在磁铁上方。
06:11
But how many fluxons, how many magnetic strands are there in a single disk like this?
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但在这样一个简单的磁片中,有多少磁通量子,有多少磁力束呢?
06:17
Well, we can calculate it, and it turns out, quite a lot.
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好吧,我们可以计算出来, 结果显示,数量还是很多的。
06:20
One hundred billion strands of magnetic field inside this three-inch disk.
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在这个三英寸厚的磁片中有一千亿的磁场束。
06:27
But that's not the amazing part yet, because there is something I haven't told you yet.
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但这还不是最惊人的部分, 因为还有一些东西我没告诉你们。
06:32
And, yeah, the amazing part is that this superconductor that you see here
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是的,最惊人的部分在于 这个你们所见到超导体
06:37
is only half a micron thick. It's extremely thin.
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仅仅是半微米厚。非常薄。
06:45
And this extremely thin layer is able to levitate more than 70,000 times its own weight.
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这片极薄的磁片能够悬浮它自重70000倍的物体。
06:54
It's a remarkable effect. It's very strong.
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这是十分惊人的反应。非常强大。
07:00
Now, I can extend this circular magnet,
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现在,我可以延伸这个环形磁铁,
07:04
and make whatever track I want.
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做出任何我想要的轨迹。
07:08
For example, I can make a large circular rail here.
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比如,我可以做出一个巨大的环形轨道。
07:12
And when I place the superconducting disk on top of this rail,
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当我把超导磁片放在轨道上方时,
07:19
it moves freely.
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它做自由运动。
07:23
(Applause)
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(掌声)
07:33
And again, that's not all. I can adjust its position like this, and rotate,
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这还不是全部哦。 我可以像这样调整它的位置,翻转,
07:37
and it freely moves in this new position.
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它在新的位置上做自由运动。
07:44
And I can even try a new thing; let's try it for the first time.
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我甚至可以尝试一件新的事情; 我们来首次尝试一下。
07:48
I can take this disk and put it here,
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我能把这个磁片放在这里,
07:54
and while it stays here -- don't move --
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当它停留在这里--不要移动--
07:57
I will try to rotate the track,
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我会尝试将轨道翻转,
08:04
and hopefully, if I did it correctly,
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希望,如果我做对了,
08:06
it stays suspended.
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它会保持悬挂在半空。
08:08
(Applause)
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(掌声)
08:18
You see, it's quantum locking, not levitation.
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你们看,这是量子锁定,而非悬浮。
08:25
Now, while I'll let it circulate for a little more,
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现在,我会让它循环更多一些,
08:29
let me tell you a little bit about superconductors.
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让我告诉大家一些关于超导体的知识。
08:32
Now -- (Laughter) --
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现在--(笑声)--
08:38
So we now know that we are able to transfer enormous amount of currents inside superconductors,
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好的,现在我们都了解了 我们能够传输超导体内部的大量电流,
08:45
so we can use them to produce strong magnetic fields,
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那么我们能够利用它们制造强大的磁场,
08:50
such as needed in MRI machines, particle accelerators and so on.
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诸如在核磁共振成像仪,粒子加速器等机器中所需要的。
08:55
But we can also store energy using superconductors,
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但我们也能够用超导体存储能量,
09:00
because we have no dissipation.
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因为超导体没有能量损耗。
09:02
And we could also produce power cables, to transfer enormous amounts of current between power stations.
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我们还能制造电缆,在电站之间传输大量电流。
09:09
Imagine you could back up a single power station with a single superconducting cable.
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想象一下,你们能够只用一根超导电缆支撑一个发电站。
09:18
But what is the future of quantum levitation and quantum locking?
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但量子悬浮和锁定的未来将何去何从呢?
09:23
Well, let me answer this simple question by giving you an example.
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好吧,我就给你们举个例子来回答这个简单的问题。
09:30
Imagine you would have a disk similar to the one I have here in my hand,
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想象一下你有一个和我手中差不多的磁片,
09:36
three-inch diameter, with a single difference.
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3英尺直径,唯一的区别是
09:40
The superconducting layer, instead of being half a micron thin,
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超导层,不是半微米厚,
09:45
being two millimeters thin, quite thin.
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而是2毫米薄,相当薄。
09:48
This two-millimeter-thin superconducting layer could hold 1,000 kilograms, a small car, in my hand.
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我手中这2毫米厚的超导层能够控制住一辆小轿车。
09:59
Amazing. Thank you.
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太神奇了。 谢谢。
10:02
(Applause)
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(掌声)
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