TEDGlobal 2012
Boaz Almog: The levitating superconductor
Boaz Almog: Lebdeči superprevodnik
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Kako lahko super-tanki disk, premera dobrih sedem centimetrov, v lebdenju nosi svojo 70.000-kratno težo? Boaz Almog nadvse zanimivo in futuristično prikaže pojav, poznan kot kvantna vklenjenost, ki superprevodnemu disku omogoča, da pluje nad magnetno tirnico -- popolnoma brez trenja in brez izgube energije.
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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Pojav, ki ste ga tu na kratko videli,
00:29
is called quantum levitation and quantum locking.
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se imenuje kvantno lebdenje
in kvantna vklenjenost.
in kvantna vklenjenost.
00:36
And the object that was levitating here
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Predmet, ki je tu lebdel,
00:40
is called a superconductor.
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pa se imenuje superprevodnik.
00:42
Superconductivity is a quantum state of matter,
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Superprevodnost je kvantno stanje snovi,
00:47
and it occurs only below a certain critical temperature.
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ki se pojavi le izpod določene
kritične temperature.
kritične temperature.
00:52
Now, it's quite an old phenomenon;
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Gre za precej star pojav,
00:54
it was discovered 100 years ago.
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ki so ga odkrili pred 100 leti.
00:56
However, only recently,
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Ampak šele v zadnjem času,
00:58
due to several technological advancements,
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po zaslugi tehnološkega napredka,
01:00
we are now able to demonstrate to you
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vam lahko pokažemo
01:03
quantum levitation and quantum locking.
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kvantno lebdenje in kvantno vklenjenost.
01:07
So, a superconductor is defined by two properties.
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Superprevodnik označujeta dve lastnosti.
01:12
The first is zero electrical resistance,
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Prva: električna upornost je enaka nič,
01:16
and the second is the expulsion of a magnetic field from the interior of the superconductor.
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in druga: magnetno polje je izrinjeno
iz notranjosti superprevodnika.
iz notranjosti superprevodnika.
01:23
That sounds complicated, right?
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Sliši se zapleteno, kajne?
01:26
But what is electrical resistance?
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Torej, kaj je električna upornost.
01:29
So, electricity is the flow of electrons inside a material.
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No, elektrika je tok elektronov v snovi.
01:35
And these electrons, while flowing,
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Ti elektroni med svojim tokom
01:38
they collide with the atoms, and in these collisions
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trkajo z atomi in ob teh trkih
01:41
they lose a certain amount of energy.
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izgubijo nekaj energije.
01:43
And they dissipate this energy in the form of heat, and you know that effect.
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To energijo razsipajo v obliki
toplote, saj poznate ta efekt.
toplote, saj poznate ta efekt.
01:49
However, inside a superconductor there are no collisions,
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Znotraj superprevodnika pa ni trkov
01:55
so there is no energy dissipation.
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in zato se tudi energija ne razsipa.
01:59
It's quite remarkable. Think about it.
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To je nekaj posebnega, kar pomislite.
02:02
In classical physics, there is always some friction, some energy loss.
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V klasični fiziki je vedno nekaj
trenja, nekaj izgube energije.
trenja, nekaj izgube energije.
02:07
But not here, because it is a quantum effect.
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Tukaj pa ne, ker gre za kvantni efekt.
02:11
But that's not all, because superconductors don't like magnetic fields.
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A to še ni vse, saj superprevodniki
ne marajo magnetnega polja.
ne marajo magnetnega polja.
02:20
So a superconductor will try to expel magnetic field from the inside,
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Tako bo superprevodnik poskušal
izriniti magnetno polje iz notranjosti
izriniti magnetno polje iz notranjosti
02:24
and it has the means to do that by circulating currents.
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in sicer s pomočjo krožnih tokov.
02:31
Now, the combination of both effects --
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No, kombinacija obeh efektov --
02:34
the expulsion of magnetic fields and zero electrical resistance --
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izrinjeno magnetno polje in
električna upornost enaka nič --
električna upornost enaka nič --
02:40
is exactly a superconductor.
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pa je točno superprevodnik.
02:43
But the picture isn't always perfect, as we all know,
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Vendar vemo, da stvari
niso vedno tako popolne
niso vedno tako popolne
02:47
and sometimes strands of magnetic field remain inside the superconductor.
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in včasih silnice magnetnega polja
ostanejo v notranjosti superprevodnika.
ostanejo v notranjosti superprevodnika.
02:54
Now, under proper conditions, which we have here,
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No, pod določenimi pogoji,
kot jih imamo tukaj,
kot jih imamo tukaj,
02:58
these strands of magnetic field can be trapped inside the superconductor.
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so te silnice magnetnega polja
lahko ujete znotraj superprevodnika.
lahko ujete znotraj superprevodnika.
03:03
And these strands of magnetic field inside the superconductor,
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Te silnice magnetnega polja
znotraj superprevodnika
znotraj superprevodnika
03:09
they come in discrete quantities.
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se pojavljajo kot diskretne količine.
03:12
Why? Because it is a quantum phenomenon. It's quantum physics.
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Zakaj? Zato, ker gre za kvantni pojav.
To je kvantna fizika.
To je kvantna fizika.
03:16
And it turns out that they behave like quantum particles.
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Izkaže se, da se vedejo kot kvantni delci.
03:20
In this movie here, you can see how they flow one by one discretely.
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V tem filmčku lahko vidite,
kako tečejo diskretno, ena po ena.
kako tečejo diskretno, ena po ena.
03:25
This is strands of magnetic field. These are not particles,
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To so silnice magnetnega polja.
To niso delci,
To niso delci,
03:29
but they behave like particles.
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vendar se vedejo kot delci.
03:33
So, this is why we call this effect quantum levitation and quantum locking.
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No, zato ta efekt imenujemo
kvantno lebdenje in kvantna vklenjenost.
kvantno lebdenje in kvantna vklenjenost.
03:38
But what happens to the superconductor when we put it inside a magnetic field?
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A, kaj se zgodi s superprevodnikom,
če ga postavimo v magnetno polje?
če ga postavimo v magnetno polje?
03:44
Well, first there are strands of magnetic field left inside,
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Kot prvo, nekaj silnic
magnetnega polja je ostalo znotraj,
magnetnega polja je ostalo znotraj,
03:48
but now the superconductor doesn't like them moving around,
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vendar superprevodnik ne mara,
da bi se pomikale naokoli,
da bi se pomikale naokoli,
03:52
because their movements dissipate energy,
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saj njihovi premiki razsipajo energijo,
03:56
which breaks the superconductivity state.
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to pa prekine stanje superprevodnosti.
03:59
So what it actually does, it locks these strands,
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Dejansko vklene te silnice,
04:03
which are called fluxons, and it locks these fluxons in place.
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ki se imenujejo fluksoni, in
jih drži vklenjene na mestu.
jih drži vklenjene na mestu.
04:09
And by doing that, what it actually does is locking itself in place.
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S tem pa pravzaprav sebe
vklene v določen položaj.
vklene v določen položaj.
04:15
Why? Because any movement of the superconductor will change their place,
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Zakaj? Ker bi katerikoli premik
superprevodnika spremenil njihov položaj,
superprevodnika spremenil njihov položaj,
04:24
will change their configuration.
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oziroma spremenil njihovo razporeditev.
04:26
So we get quantum locking. And let me show you how this works.
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Na ta način dobimo kvantno vklenjenost.
Naj vam pokažem, kako to deluje.
Naj vam pokažem, kako to deluje.
04:31
I have here a superconductor, which I wrapped up so it'd stay cold long enough.
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Tukaj imam superprevodnik, ki sem ga
zavil, da bi dovolj dolgo ostal hladen.
zavil, da bi dovolj dolgo ostal hladen.
04:37
And when I place it on top of a regular magnet,
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Ko ga postavim na navaden magnet,
04:42
it just stays locked in midair.
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kar ostane vklenjen v zraku.
04:46
(Applause)
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(Aplavz)
04:50
Now, this is not just levitation. It's not just repulsion.
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To ni le lebdenje. To ni le odboj.
04:54
I can rearrange the fluxons, and it will be locked in this new configuration.
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Fluksone lahko prerazporedim in potem
ostane vklenjen v novi razporeditvi.
ostane vklenjen v novi razporeditvi.
04:59
Like this, or move it slightly to the right or to the left.
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Takole. Ali pa ga pomaknem desno ali levo.
05:03
So, this is quantum locking -- actually locking -- three-dimensional locking of the superconductor.
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To je torej kvantna vklenjenost
- dejansko vklenjenost -
- dejansko vklenjenost -
tridimenzionalna vklenjenost
superprevodnika.
superprevodnika.
Seveda ga lahko obrnem na glavo
05:11
Of course, I can turn it upside down,
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05:13
and it will remain locked.
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in bo spet vklenjen.
05:16
Now, now that we understand that this so-called levitation is actually locking,
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No, sedaj razumemo, da ja to t. i.
lebdenje dejansko vklenjenost.
lebdenje dejansko vklenjenost.
05:25
Yeah, we understand that.
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Ja, to razumemo.
05:29
You won't be surprised to hear that if I take this circular magnet,
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Ne bo vas presenetilo, da ko
bomo vzeli ta krožni magnet,
bomo vzeli ta krožni magnet,
05:33
in which the magnetic field is the same all around,
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po katerem je magnetno polje povsod enako,
05:37
the superconductor will be able to freely rotate around the axis of the magnet.
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se bo superprevodnik lahko
prosto vrtel okrog osi magneta.
prosto vrtel okrog osi magneta.
05:43
Why? Because as long as it rotates, the locking is maintained.
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Zakaj? Dokler se vrti,
se vklenjenost vzdržuje.
se vklenjenost vzdržuje.
05:49
You see? I can adjust and I can rotate the superconductor.
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Vidite? Superprevodnik lahko
premaknem in lahko ga vrtim.
premaknem in lahko ga vrtim.
05:55
We have frictionless motion. It is still levitating, but can move freely all around.
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Imamo gibanje brez trenja. Še vedno
lebdi, vendar lahko prosto potuje okrog.
lebdi, vendar lahko prosto potuje okrog.
06:02
So, we have quantum locking and we can levitate it on top of this magnet.
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Torej imamo kvantno vklenjenost in
lahko dosežemo, da lebdi nad magnetom.
lahko dosežemo, da lebdi nad magnetom.
06:11
But how many fluxons, how many magnetic strands are there in a single disk like this?
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Koliko fluksonov, koliko magnetnih silnic
pa je v posameznem disku, kot je ta?
pa je v posameznem disku, kot je ta?
06:18
Well, we can calculate it, and it turns out, quite a lot.
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No, to lahko izračunamo in
izkaže se, da jih je kar precej.
izkaže se, da jih je kar precej.
06:21
One hundred billion strands of magnetic field inside this three-inch disk.
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Sto milijard magnetnih silnic
je v tem disku premera 7,5 cm.
je v tem disku premera 7,5 cm.
06:28
But that's not the amazing part yet, because there is something I haven't told you yet.
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Ampak to še ni tisti osupljivi del,
nečesa vam namreč še nisem povedal.
nečesa vam namreč še nisem povedal.
06:32
And, yeah, the amazing part is that this superconductor that you see here
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Osupljivo je, da je superprevodnik pred vami
06:38
is only half a micron thick. It's extremely thin.
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debel le pol mikrona. Zelo tanek je.
06:45
And this extremely thin layer is able to levitate more than 70,000 times its own weight.
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Ta izredno tanka plast je sposobna v lebdenju
nositi več kot svojo 70.000-kratno težo.
nositi več kot svojo 70.000-kratno težo.
06:55
It's a remarkable effect. It's very strong.
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To je izreden učinek. Velika moč.
07:01
Now, I can extend this circular magnet,
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Ta krožni magnet lahko razširim
07:04
and make whatever track I want.
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in naredim kakršnokoli progo.
07:09
For example, I can make a large circular rail here.
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Na primer, lahko naredim
veliko krožno progo tukaj.
veliko krožno progo tukaj.
07:13
And when I place the superconducting disk on top of this rail,
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In ko superprevodni disk
položim na to progo,
položim na to progo,
07:20
it moves freely.
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se prosto giblje.
07:24
(Applause)
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(Aplavz)
07:33
And again, that's not all. I can adjust its position like this, and rotate,
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In to še ni vse. Njegov položaj
lahko spremenim, takole, in ga zavrtim
lahko spremenim, takole, in ga zavrtim
07:38
and it freely moves in this new position.
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in se prosto giblje v tem položaju.
07:45
And I can even try a new thing; let's try it for the first time.
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In lahko poskusim še nekaj novega -
pa poskusimo to, prvič.
pa poskusimo to, prvič.
07:49
I can take this disk and put it here,
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Ta disk lahko postavim sem
07:55
and while it stays here -- don't move --
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in medtem ko je tu -- miruj --
07:58
I will try to rotate the track,
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bom poskusil obrniti progo
08:04
and hopefully, if I did it correctly,
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in upam da bo, če sem vse naredil prav,
08:07
it stays suspended.
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obvisel v zraku.
08:09
(Applause)
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(Aplavz)
08:18
You see, it's quantum locking, not levitation.
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Vidite, gre za kvantno vklenjenost,
ne za lebdenje.
ne za lebdenje.
08:25
Now, while I'll let it circulate for a little more,
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Medtem naj še malo kroži,
08:29
let me tell you a little bit about superconductors.
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jaz pa vam povem še
nekaj o superprevodnikih.
nekaj o superprevodnikih.
08:33
Now -- (Laughter) --
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No -- (Smeh) ---
08:39
So we now know that we are able to transfer enormous amount of currents inside superconductors,
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Vemo že, da znamo prenašati velikanske
količine tokov znotraj superprevodnikov
količine tokov znotraj superprevodnikov
08:46
so we can use them to produce strong magnetic fields,
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in zato z njimi lahko naredimo
močna magnetna polja,
močna magnetna polja,
08:51
such as needed in MRI machines, particle accelerators and so on.
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takšna, kot jih potrebujejo MRI-naprave,
pospeševalniki delcev itd.
pospeševalniki delcev itd.
08:56
But we can also store energy using superconductors,
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Ampak s pomočjo superprevodnikov
lahko tudi shranjujemo energijo,
lahko tudi shranjujemo energijo,
09:01
because we have no dissipation.
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saj ni izgub.
09:02
And we could also produce power cables, to transfer enormous amounts of current between power stations.
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Lahko bi izdelali električne kable za
prenos velikanskih tokov med elektrarnami.
prenos velikanskih tokov med elektrarnami.
09:10
Imagine you could back up a single power station with a single superconducting cable.
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Predstavljajte si, da bi
posamezno elektrarno ob izpadu
posamezno elektrarno ob izpadu
lahko nadomestili prek enega
samega superprevodnega kabla.
samega superprevodnega kabla.
A, kaj je prihodnost kvantnega lebdenja
in kvantne vklenjenosti?
in kvantne vklenjenosti?
09:19
But what is the future of quantum levitation and quantum locking?
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09:23
Well, let me answer this simple question by giving you an example.
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Naj na to preprosto vprašanje
odgovorim s primerom.
odgovorim s primerom.
09:30
Imagine you would have a disk similar to the one I have here in my hand,
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Predstavljajte si, da imate podoben
disk, kot je ta v moji roki,
disk, kot je ta v moji roki,
09:37
three-inch diameter, with a single difference.
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premera 7,5 cm, a z eno razliko.
09:41
The superconducting layer, instead of being half a micron thin,
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Superprevodna plast bi bila
namesto pol mikrona debela
namesto pol mikrona debela
09:46
being two millimeters thin, quite thin.
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dva milimetra, kar je še vedno tanko.
09:49
This two-millimeter-thin superconducting layer could hold 1,000 kilograms, a small car, in my hand.
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Ta dvo-milimetrska superprevodna
plast bi lahko nosila
plast bi lahko nosila
1.000 kilogramov, majhen avto, v moji roki.
10:00
Amazing. Thank you.
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Osupljivo. Hvala.
10:03
(Applause)
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(Aplavz)
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