1
00:00:09,752 --> 00:00:14,070
The phenomenon you saw here for a brief moment

2
00:00:14,070 --> 00:00:20,459
is called quantum levitation and quantum locking.

3
00:00:20,459 --> 00:00:24,348
And the object that was levitating here

4
00:00:24,348 --> 00:00:26,349
is called a superconductor.

5
00:00:26,349 --> 00:00:31,941
Superconductivity is a quantum state of matter,

6
00:00:31,941 --> 00:00:36,198
and it occurs only below a certain critical temperature.

7
00:00:36,198 --> 00:00:38,544
Now, it's quite an old phenomenon;

8
00:00:38,544 --> 00:00:40,310
it was discovered 100 years ago.

9
00:00:40,310 --> 00:00:42,436
However, only recently,

10
00:00:42,436 --> 00:00:44,798
due to several technological advancements,

11
00:00:44,798 --> 00:00:47,470
we are now able to demonstrate to you

12
00:00:47,470 --> 00:00:51,216
quantum levitation and quantum locking.

13
00:00:51,216 --> 00:00:57,061
So, a superconductor is defined by two properties.

14
00:00:57,061 --> 00:01:00,517
The first is zero electrical resistance,

15
00:01:00,517 --> 00:01:07,406
and the second is the expulsion of a magnetic field from the interior of the superconductor.

16
00:01:07,406 --> 00:01:10,301
That sounds complicated, right?

17
00:01:10,301 --> 00:01:13,173
But what is electrical resistance?

18
00:01:13,173 --> 00:01:19,422
So, electricity is the flow of electrons inside a material.

19
00:01:19,422 --> 00:01:22,771
And these electrons, while flowing,

20
00:01:22,771 --> 00:01:25,459
they collide with the atoms, and in these collisions

21
00:01:25,459 --> 00:01:27,675
they lose a certain amount of energy.

22
00:01:27,675 --> 00:01:33,276
And they dissipate this energy in the form of heat, and you know that effect.

23
00:01:33,276 --> 00:01:39,195
However, inside a superconductor there are no collisions,

24
00:01:39,195 --> 00:01:43,887
so there is no energy dissipation.

25
00:01:43,887 --> 00:01:46,868
It's quite remarkable. Think about it.

26
00:01:46,868 --> 00:01:51,947
In classical physics, there is always some friction, some energy loss.

27
00:01:51,947 --> 00:01:55,985
But not here, because it is a quantum effect.

28
00:01:56,016 --> 00:02:04,702
But that's not all, because superconductors don't like magnetic fields.

29
00:02:04,702 --> 00:02:09,019
So a superconductor will try to expel magnetic field from the inside,

30
00:02:09,019 --> 00:02:15,142
and it has the means to do that by circulating currents.

31
00:02:15,142 --> 00:02:18,132
Now, the combination of both effects --

32
00:02:18,132 --> 00:02:24,132
the expulsion of magnetic fields and zero electrical resistance --

33
00:02:24,132 --> 00:02:27,300
is exactly a superconductor.

34
00:02:27,300 --> 00:02:31,516
But the picture isn't always perfect, as we all know,

35
00:02:31,516 --> 00:02:38,901
and sometimes strands of magnetic field remain inside the superconductor.

36
00:02:38,901 --> 00:02:42,555
Now, under proper conditions, which we have here,

37
00:02:42,555 --> 00:02:47,645
these strands of magnetic field can be trapped inside the superconductor.

38
00:02:47,645 --> 00:02:53,902
And these strands of magnetic field inside the superconductor,

39
00:02:53,902 --> 00:02:56,747
they come in discrete quantities.

40
00:02:56,747 --> 00:03:00,393
Why? Because it is a quantum phenomenon. It's quantum physics.

41
00:03:00,393 --> 00:03:04,243
And it turns out that they behave like quantum particles.

42
00:03:04,243 --> 00:03:09,822
In this movie here, you can see how they flow one by one discretely.

43
00:03:09,822 --> 00:03:13,715
This is strands of magnetic field. These are not particles,

44
00:03:13,715 --> 00:03:18,010
but they behave like particles.

45
00:03:18,010 --> 00:03:22,204
So, this is why we call this effect quantum levitation and quantum locking.

46
00:03:22,204 --> 00:03:28,267
But what happens to the superconductor when we put it inside a magnetic field?

47
00:03:28,267 --> 00:03:32,852
Well, first there are strands of magnetic field left inside,

48
00:03:32,852 --> 00:03:36,972
but now the superconductor doesn't like them moving around,

49
00:03:36,972 --> 00:03:40,420
because their movements dissipate energy,

50
00:03:40,420 --> 00:03:43,366
which breaks the superconductivity state.

51
00:03:43,366 --> 00:03:47,724
So what it actually does, it locks these strands,

52
00:03:47,724 --> 00:03:53,476
which are called fluxons, and it locks these fluxons in place.

53
00:03:53,476 --> 00:03:59,764
And by doing that, what it actually does is locking itself in place.

54
00:03:59,764 --> 00:04:08,980
Why? Because any movement of the superconductor will change their place,

55
00:04:08,980 --> 00:04:10,787
will change their configuration.

56
00:04:10,787 --> 00:04:16,084
So we get quantum locking. And let me show you how this works.

57
00:04:16,084 --> 00:04:21,844
I have here a superconductor, which I wrapped up so it'd stay cold long enough.

58
00:04:21,844 --> 00:04:26,308
And when I place it on top of a regular magnet,

59
00:04:26,308 --> 00:04:30,180
it just stays locked in midair.

60
00:04:30,180 --> 00:04:34,245
(Applause)

61
00:04:34,245 --> 00:04:38,291
Now, this is not just levitation. It's not just repulsion.

62
00:04:38,291 --> 00:04:43,412
I can rearrange the fluxons, and it will be locked in this new configuration.

63
00:04:43,412 --> 00:04:47,436
Like this, or move it slightly to the right or to the left.

64
00:04:47,436 --> 00:04:55,187
So, this is quantum locking -- actually locking -- three-dimensional locking of the superconductor.

65
00:04:55,187 --> 00:04:57,347
Of course, I can turn it upside down,

66
00:04:57,347 --> 00:05:00,253
and it will remain locked.

67
00:05:00,253 --> 00:05:09,475
Now, now that we understand that this so-called levitation is actually locking,

68
00:05:09,475 --> 00:05:13,789
Yeah, we understand that.

69
00:05:13,789 --> 00:05:18,051
You won't be surprised to hear that if I take this circular magnet,

70
00:05:18,051 --> 00:05:22,019
in which the magnetic field is the same all around,

71
00:05:22,019 --> 00:05:27,955
the superconductor will be able to freely rotate around the axis of the magnet.

72
00:05:27,955 --> 00:05:33,979
Why? Because as long as it rotates, the locking is maintained.

73
00:05:33,979 --> 00:05:40,005
You see? I can adjust and I can rotate the superconductor.

74
00:05:40,005 --> 00:05:46,667
We have frictionless motion. It is still levitating, but can move freely all around.

75
00:05:46,667 --> 00:05:55,947
So, we have quantum locking and we can levitate it on top of this magnet.

76
00:05:55,947 --> 00:06:02,443
But how many fluxons, how many magnetic strands are there in a single disk like this?

77
00:06:02,443 --> 00:06:05,324
Well, we can calculate it, and it turns out, quite a lot.

78
00:06:05,324 --> 00:06:12,692
One hundred billion strands of magnetic field inside this three-inch disk.

79
00:06:12,692 --> 00:06:16,796
But that's not the amazing part yet, because there is something I haven't told you yet.

80
00:06:16,796 --> 00:06:22,412
And, yeah, the amazing part is that this superconductor that you see here

81
00:06:22,412 --> 00:06:29,937
is only half a micron thick. It's extremely thin.

82
00:06:29,937 --> 00:06:39,499
And this extremely thin layer is able to levitate more than 70,000 times its own weight.

83
00:06:39,499 --> 00:06:45,332
It's a remarkable effect. It's very strong.

84
00:06:45,332 --> 00:06:48,909
Now, I can extend this circular magnet,

85
00:06:48,909 --> 00:06:53,690
and make whatever track I want.

86
00:06:53,690 --> 00:06:57,619
For example, I can make a large circular rail here.

87
00:06:57,619 --> 00:07:04,502
And when I place the superconducting disk on top of this rail,

88
00:07:04,502 --> 00:07:08,611
it moves freely.

89
00:07:08,611 --> 00:07:17,992
(Applause)

90
00:07:17,992 --> 00:07:22,733
And again, that's not all. I can adjust its position like this, and rotate,

91
00:07:22,733 --> 00:07:29,174
and it freely moves in this new position.

92
00:07:29,174 --> 00:07:33,612
And I can even try a new thing; let's try it for the first time.

93
00:07:33,612 --> 00:07:39,556
I can take this disk and put it here,

94
00:07:39,556 --> 00:07:42,540
and while it stays here -- don't move --

95
00:07:42,540 --> 00:07:49,098
I will try to rotate the track,

96
00:07:49,098 --> 00:07:51,397
and hopefully, if I did it correctly,

97
00:07:51,397 --> 00:07:53,540
it stays suspended.

98
00:07:53,540 --> 00:08:02,989
(Applause)

99
00:08:02,989 --> 00:08:09,830
You see, it's quantum locking, not levitation.

100
00:08:09,830 --> 00:08:13,965
Now, while I'll let it circulate for a little more,

101
00:08:13,965 --> 00:08:17,668
let me tell you a little bit about superconductors.

102
00:08:17,668 --> 00:08:23,214
Now -- (Laughter) --

103
00:08:23,214 --> 00:08:30,237
So we now know that we are able to transfer enormous amount of currents inside superconductors,

104
00:08:30,237 --> 00:08:35,460
so we can use them to produce strong magnetic fields,

105
00:08:35,460 --> 00:08:40,646
such as needed in MRI machines, particle accelerators and so on.

106
00:08:40,646 --> 00:08:45,206
But we can also store energy using superconductors,

107
00:08:45,206 --> 00:08:47,095
because we have no dissipation.

108
00:08:47,095 --> 00:08:54,277
And we could also produce power cables, to transfer enormous amounts of current between power stations.

109
00:08:54,277 --> 00:09:03,283
Imagine you could back up a single power station with a single superconducting cable.

110
00:09:03,283 --> 00:09:07,759
But what is the future of quantum levitation and quantum locking?

111
00:09:07,759 --> 00:09:14,898
Well, let me answer this simple question by giving you an example.

112
00:09:14,898 --> 00:09:21,311
Imagine you would have a disk similar to the one I have here in my hand,

113
00:09:21,311 --> 00:09:25,190
three-inch diameter, with a single difference.

114
00:09:25,190 --> 00:09:30,375
The superconducting layer, instead of being half a micron thin,

115
00:09:30,375 --> 00:09:33,463
being two millimeters thin, quite thin.

116
00:09:33,463 --> 00:09:44,198
This two-millimeter-thin superconducting layer could hold 1,000 kilograms, a small car, in my hand.

117
00:09:44,198 --> 00:09:47,494
Amazing. Thank you.

118
00:09:47,494 --> 00:10:02,574
(Applause)