TEDGlobal 2012
Boaz Almog: The levitating superconductor
Boaz Almog “悬浮” 一个超导体
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一个超薄的3英尺磁片如何使它自重7万倍的物体悬浮？在这个引人入胜且具有未来感的演示中，Boaz Almog 展示了量子锁定效应如何使一片超导体磁片在磁力轨道上漂浮--完全无摩擦，且无能量损耗。
Boaz Almog - Quantum Researcher
Boaz Almog uses quantum physics to levitate and trap objects in midair. Call it "quantum levitation." Full bio
Boaz Almog uses quantum physics to levitate and trap objects in midair. Call it "quantum levitation." Full bio
Double-click the English transcript below to play the video.
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。
00:36
And the object that was levitating here
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这个悬浮在这里的物体
00:40
is called a superconductor.
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被称为超导体。
00:42
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。
00:52
Now, it's quite an old phenomenon;
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现在，这是一个比较老的现象了；
00:54
it was discovered 100 years ago.
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100年前被发现。
00:56
However, only recently,
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然而，就在最近，
00:58
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
01:03
quantum levitation and quantum locking.
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量子悬浮和量子锁定。
01:07
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，
01:16
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。
01:23
That sounds complicated, right?
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这听起来有点复杂，是吗？
01:26
But what is electrical resistance?
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但什么是电阻呢？
01:29
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。
01:35
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
01:41
they lose a certain amount of energy.
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它们损失一定的能量。
01:43
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。
你们知道这种效果的。
01:49
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，
01:55
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。
02:20
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。
02:31
Now, the combination of both effects --
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现在，两种效应相结合--
02:34
the expulsion of magnetic fields and zero electrical resistance --
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驱逐磁场和零电阻--
02:40
is exactly a superconductor.
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就是超导体。
02:43
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，
02:47
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，
02:58
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。
03:03
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。
是量子物理学。
03:16
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。
03:20
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，
不是粒子，
03:29
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。
03:38
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？
它发生了什么变化呢？
03:44
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，
03:56
which breaks the superconductivity state.
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这样会破坏超导体状态。
03:59
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，
它锁定了这些磁场束，
04:03
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。
它把这些磁通量子锁定在原地。
04:09
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。
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。
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，
04:42
it just stays locked in midair.
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它就被锁定在半空中。
04:46
(Applause)
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（鼓掌）
04:50
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。
不仅仅是相斥。
04:54
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。
它就能够被锁定在这个新的装置内。
04:59
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。
05:03
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。
超导体的三维锁定。
05:11
Of course, I can turn it upside down,
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当然，我也可以把它倒过来，
05:13
and it will remain locked.
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它还是会保持锁定。
05:16
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，
05:25
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，
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。
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。
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。
它仍然在悬浮，但能够自由移动。
06:02
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。
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？
06:18
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。
结果显示，数量还是很多的。
06:21
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。
06:28
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。
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
这个你们所见到超导体
06:38
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。
06:55
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。
07:01
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。
07:09
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。
07:13
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，
07:20
it moves freely.
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它做自由运动。
07:24
(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，
我可以像这样调整它的位置，翻转，
07:38
and it freely moves in this new position.
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它在新的位置上做自由运动。
07:45
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。
我们来首次尝试一下。
07:49
I can take this disk and put it here,
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我能把这个磁片放在这里，
07:55
and while it stays here -- don't move --
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当它停留在这里--不要移动--
07:58
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，
08:07
it stays suspended.
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它会保持悬挂在半空。
08:09
(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。
08:33
Now -- (Laughter) --
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现在--（笑声）--
08:39
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，
我们能够传输超导体内部的大量电流，
08:46
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，
08:51
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。
08:56
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，
09:01
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。
09:10
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。
09:19
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，
09:37
three-inch diameter, with a single difference.
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3英尺直径，唯一的区别是
09:41
The superconducting layer, instead of being half a micron thin,
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超导层，不是半微米厚，
09:46
being two millimeters thin, quite thin.
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而是2毫米薄，相当薄。
09:49
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。
10:00
Amazing. Thank you.
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太神奇了。
谢谢。
谢谢。
10:03
(Applause)
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（掌声）
ABOUT THE SPEAKER
Boaz Almog - Quantum ResearcherBoaz Almog uses quantum physics to levitate and trap objects in midair. Call it "quantum levitation."
Why you should listen
In October 2011, Boaz Almog demonstrated how a superconducting disk can be trapped in a surrounding magnetic field to levitate above it, a phenomenon called “quantum levitation.” This demonstration, seemingly taken from a sci-fi movie, is the result of many years of R&D on high-quality superconductors. By using exceptional superconductors cooled in liquid nitrogen, Almog and his colleague Mishael Azoulay at the superconductivity group at Tel Aviv University (lead by Prof. Guy Deutscher) were able to demonstrate a quantum effect that, although well known to physicists worldwide, had never been seen and demonstrated in such a compelling way.
Experiment credits:
Prof. Guy Deutscher, Mishael Azoulay and Boaz Almog
High Tc Superconductivity Group
School of Physics and Astronomy
Tel Aviv University
Watch more footage from this demo >>
Boaz Almog | Speaker | TED.com