TEDGlobal 2012
Boaz Almog: The levitating superconductor
Boaz Almog "levitira" supravodič
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Kako je moguće da jedan nevjerojatno tanak disk, promjera 7,6 cm, levitira stvar težu od njega samog 70,000 puta? U svojoj fascinantnoj, futurističkoj demonstraciji, Boaz Almog pokazuje kako efekt kvantnog zaključavanja omogućuje supravodiču da lebdi iznad magnetne trake -- bez ikakvog trenja i bez gubitka 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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Fenomen koji ste vidjeli, u jednom kratkom trenutku
00:29
is called quantum levitation and quantum locking.
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zove se kvantna levitacija i kvantno zaključavanje.
00:36
And the object that was levitating here
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Objekt koji je levitirao
00:40
is called a superconductor.
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zove se supravodič.
00:42
Superconductivity is a quantum state of matter,
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Supravodljivost je kvantno stanje stvari,
00:47
and it occurs only below a certain critical temperature.
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koje se događa samo ispod određenih temperatura.
00:52
Now, it's quite an old phenomenon;
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Zapravo je to fenomen koji već dugo poznajemo.
00:54
it was discovered 100 years ago.
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Otkriven je prije stotinu godina.
00:56
However, only recently,
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Međutim, tek odnedavno,
00:58
due to several technological advancements,
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zahvaljujući tehnološkom napretku,
01:00
we are now able to demonstrate to you
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možemo vam demonstrirati
01:03
quantum levitation and quantum locking.
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kvantnu levitaciju i kvantno zaključavanje.
01:07
So, a superconductor is defined by two properties.
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Dakle, supravodič je određen dvama svojstvima.
01:12
The first is zero electrical resistance,
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Prvo svojstvo je odsustvo električnog otpora,
01:16
and the second is the expulsion of a magnetic field from the interior of the superconductor.
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a drugo je izbacivanje magnetskog polja iz unutrašnjosti supravodiča.
01:23
That sounds complicated, right?
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Zvuči kompilcirano, zar ne?
01:26
But what is electrical resistance?
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No, što je električni otpor?
01:29
So, electricity is the flow of electrons inside a material.
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Elektricitet je protok elektrona unutar materijala.
01:35
And these electrons, while flowing,
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I ti elektroni se u svom kretanju
01:38
they collide with the atoms, and in these collisions
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sudaraju s atomima, i u tim sudarima
01:41
they lose a certain amount of energy.
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gube određenu količinu energije.
01:43
And they dissipate this energy in the form of heat, and you know that effect.
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Ta se energija rasipa u vidu zagrijavanja, i to vam je poznato.
01:49
However, inside a superconductor there are no collisions,
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Međutim, unutar supravodiča nema sudaranja
01:55
so there is no energy dissipation.
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i stoga nema rasipanja energije.
01:59
It's quite remarkable. Think about it.
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To je zaista izvanredno. Razmislite o tome.
02:02
In classical physics, there is always some friction, some energy loss.
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U klasičnoj fizici, uvijek imamo trenje, uvijek se gubi nešto energije.
02:07
But not here, because it is a quantum effect.
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Ali, ne i ovdje, zbog toga što je riječ o kvantnom efektu.
02:11
But that's not all, because superconductors don't like magnetic fields.
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Ali to nije sve, zato što supravodiči ne vole magnetna polja.
02:20
So a superconductor will try to expel magnetic field from the inside,
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Zato supravodiči nastoje izbaciti magnetno polje iznutra,
02:24
and it has the means to do that by circulating currents.
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a to rade uz pomoć kružnih struja.
02:31
Now, the combination of both effects --
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Kombinacija oba efekta --
02:34
the expulsion of magnetic fields and zero electrical resistance --
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izbacivanje magnetnog polja i izostanak električnog otpora
02:40
is exactly a superconductor.
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jest supravodič.
02:43
But the picture isn't always perfect, as we all know,
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No, kako to biva, slika nije uvijek savršena
02:47
and sometimes strands of magnetic field remain inside the superconductor.
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i ponekad silnice magnetnog polja ostaju u supravodiču.
02:54
Now, under proper conditions, which we have here,
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Sada, u odgovarajućim uvjetima, kakve imamo ovdje,
02:58
these strands of magnetic field can be trapped inside the superconductor.
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silnice magnetnog polja mogu ostati zarobljene unutar supravodiča.
03:03
And these strands of magnetic field inside the superconductor,
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A te silnice unutar supravodiča
03:09
they come in discrete quantities.
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dolaze u malim količinama.
03:12
Why? Because it is a quantum phenomenon. It's quantum physics.
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Zašto? Zato što je to kvantni fenomen. Kvantna fizika.
03:16
And it turns out that they behave like quantum particles.
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I ispada da se one ponašaju poput kvantnih čestica.
03:20
In this movie here, you can see how they flow one by one discretely.
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U ovom ovdje filmu možete vidjeti kako se diskretno kreću jedna po jedna.
03:25
This is strands of magnetic field. These are not particles,
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Ovo su silnice magnetnog polja. Ovo nisu čestice,
03:29
but they behave like particles.
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ali se ponašaju poput čestica.
03:33
So, this is why we call this effect quantum levitation and quantum locking.
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Dakle, zbog toga se fenomen zove kvantna levitacija i kvantno zaključavanje.
03:38
But what happens to the superconductor when we put it inside a magnetic field?
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No, što se dešava sa supravodičem kada ga stavimo unutar magnetnog polja?
03:44
Well, first there are strands of magnetic field left inside,
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Pa, imamo silnice magnetnog polja koje su ostale unutra,
03:48
but now the superconductor doesn't like them moving around,
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ali sada supravodiču više ne odgovara da se one kreću naokolo
03:52
because their movements dissipate energy,
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jer njihovo kretanje rasipa energiju
03:56
which breaks the superconductivity state.
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i to prekida stanje supravodljivosti.
03:59
So what it actually does, it locks these strands,
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Tako da zapravo da zaključava te silnice,
04:03
which are called fluxons, and it locks these fluxons in place.
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koje se zovu fluksoni. Zaključava fluksone u mjestu.
04:09
And by doing that, what it actually does is locking itself in place.
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Na taj način on sam sebe zapravo zaključava u mjestu.
04:15
Why? Because any movement of the superconductor will change their place,
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Zašto? Zato što svaki pokret supravodiča mijenja mjesto silnica
04:24
will change their configuration.
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i njihovu konfiguraciju.
04:26
So we get quantum locking. And let me show you how this works.
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I tako dobivamo kvantno zaključavanje. Pokazat ću vam kako to funkcionira.
04:31
I have here a superconductor, which I wrapped up so it'd stay cold long enough.
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Ovdje imam supravodič koji sam umotao kako bi dovoljno dugo ostao hladan.
04:37
And when I place it on top of a regular magnet,
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I kada ga stavim na običan magnet,
04:42
it just stays locked in midair.
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on ostane zaključan u zraku.
04:46
(Applause)
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(Pljesak)
04:50
Now, this is not just levitation. It's not just repulsion.
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Pazite, ne radi se o levitaciji. Nije to obično odbijanje.
04:54
I can rearrange the fluxons, and it will be locked in this new configuration.
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Mogu prerasporediti fluksone i bit će zaključan u ovoj novoj konfiguraciji.
04:59
Like this, or move it slightly to the right or to the left.
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Na primjer, ovako. Ili ga mogu pomaknuti malo lijevo ili desno.
05:03
So, this is quantum locking -- actually locking -- three-dimensional locking of the superconductor.
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Dakle, ovo je kvantno zaključavanje -- stvarno zaključavanje -- trodimenzionalno zaključavanje supravodiča.
05:11
Of course, I can turn it upside down,
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Naravno, može se okrenuti i naglavačke
05:13
and it will remain locked.
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i ostat će zaključan.
05:16
Now, now that we understand that this so-called levitation is actually locking,
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Sada kada razumijemo da je tzv. levitacija zapravo zaključavanje,
05:25
Yeah, we understand that.
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da, to smo shvatili.
05:29
You won't be surprised to hear that if I take this circular magnet,
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Neće vas iznenaditi ako vam kažem da će, ako uzmem ovaj kružni magnet
05:33
in which the magnetic field is the same all around,
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u kojem je magnetno polje jednako na svim djelovima,
05:37
the superconductor will be able to freely rotate around the axis of the magnet.
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supravodič slobodno kružiti oko osi magneta.
05:43
Why? Because as long as it rotates, the locking is maintained.
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Zašto? Zato što dokle god rotira, održava se zaključavanje.
05:49
You see? I can adjust and I can rotate the superconductor.
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Vidite? Mogu namjestiti i rotirati supravodič.
05:55
We have frictionless motion. It is still levitating, but can move freely all around.
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Imamo kretanje bez trenja. Još uvijek levitira, ali se može slobodno kretati uokolo.
06:02
So, we have quantum locking and we can levitate it on top of this magnet.
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Dakle, imamo kvantno zaključavanje i mogućnost levitacije na vrhu magneta.
06:11
But how many fluxons, how many magnetic strands are there in a single disk like this?
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No, koliko fluksona, koliko magnetnih silnica imamo u jednom ovakvom disku?
06:18
Well, we can calculate it, and it turns out, quite a lot.
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Pa, možemo to izračunati i ispada da ih je mnogo.
06:21
One hundred billion strands of magnetic field inside this three-inch disk.
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Stotinu milijardi silnica magnetnog polja nalazi se unutar jednog ovakvog diska veličine 7,6 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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Ali, to još nije nevjerojatan dio priče, zato što postoji nešto što vam još nisam rekao.
06:32
And, yeah, the amazing part is that this superconductor that you see here
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Da, da, nevjerojatan dio priče je taj da je supravodič kojeg ovdje vidite
06:38
is only half a micron thick. It's extremely thin.
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debeo samo pola mikrona. Izuzetno je tanak.
06:45
And this extremely thin layer is able to levitate more than 70,000 times its own weight.
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I taj nevjerojatno tanki sloj može držati nešto 70,000 puta teže od vlastite težine.
06:55
It's a remarkable effect. It's very strong.
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To je nevjerojatan efekt. Izuzetno snažan.
07:01
Now, I can extend this circular magnet,
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Sada, mogu proširiti ovaj kružni magnet
07:04
and make whatever track I want.
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i napraviti kakvu god traku želim.
07:09
For example, I can make a large circular rail here.
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Na primjer, mogu napraviti veliku kružnu traku ovdje.
07:13
And when I place the superconducting disk on top of this rail,
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I kada na traku stavim supravodljivi disk,
07:20
it moves freely.
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on se slobodno kreće.
07:24
(Applause)
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(Pljesak)
07:33
And again, that's not all. I can adjust its position like this, and rotate,
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Ali opet, to nije sve, mogu ga namjestiti ovako i rotirati
07:38
and it freely moves in this new position.
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i on se slobodno kreće u tom novom položaju.
07:45
And I can even try a new thing; let's try it for the first time.
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I možemo probati i jednu novu stvar; probajmo to po prvi put.
07:49
I can take this disk and put it here,
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Mogu uzeti ovaj disk, staviti ga ovdje,
07:55
and while it stays here -- don't move --
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i dok je tu -- ne miči se --
07:58
I will try to rotate the track,
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probat ću zarotirati traku,
08:04
and hopefully, if I did it correctly,
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i nadati se, ako sam to dobro učinio,
08:07
it stays suspended.
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da će tu ostati.
08:09
(Applause)
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(Pljesak)
08:18
You see, it's quantum locking, not levitation.
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Vidite, radi se o kvantnom zaključavanju, ne o levitaciji.
08:25
Now, while I'll let it circulate for a little more,
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Sada, pustit ćemo ga da još malo kruži,
08:29
let me tell you a little bit about superconductors.
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a ja ću vam reći nešto o supravodičima.
08:33
Now -- (Laughter) --
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Sada-- (Smijeh) --
08:39
So we now know that we are able to transfer enormous amount of currents inside superconductors,
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Sada znamo da možemo prenijeti ogromne količine struje unutar saupravodiča
08:46
so we can use them to produce strong magnetic fields,
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pa ih možemo koristiti da bismo stvorili jaka magnetna polja,
08:51
such as needed in MRI machines, particle accelerators and so on.
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koja su potrebna kod MRI uređaja, ubrzivača čestica, itd.
08:56
But we can also store energy using superconductors,
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Ali unutar supravodiča možemo i spremiti energiju,
09:01
because we have no dissipation.
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zato što nema rasipanja.
09:02
And we could also produce power cables, to transfer enormous amounts of current between power stations.
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I možemo proizvesti kablove za prijenos ogromnih količina struje između elektrana.
09:10
Imagine you could back up a single power station with a single superconducting cable.
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Zamislite da možete podržati cijelu elektranu sa samo jednim supravodljivim kablom.
09:19
But what is the future of quantum levitation and quantum locking?
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No što je budućnost kvantne levitacije i kvantnog zaključavanja?
09:23
Well, let me answer this simple question by giving you an example.
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Pa, odgovorit ću vam na ovo jednostavno pitanje jednim primjerom.
09:30
Imagine you would have a disk similar to the one I have here in my hand,
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Zamislite da imate disk koji je nalik ovom ovdje kojeg imam u ruci,
09:37
three-inch diameter, with a single difference.
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7,6 centimetara u promjeru, sa samo jednom razlikom.
09:41
The superconducting layer, instead of being half a micron thin,
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Supravodljivi sloj, umjesto debljine jednog mikrona,
09:46
being two millimeters thin, quite thin.
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bude debljine dva milimetra, i dalje jako tanak.
09:49
This two-millimeter-thin superconducting layer could hold 1,000 kilograms, a small car, in my hand.
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Takav supravodljivi sloj od dva milimetra može držati 1.000 kilograma, manji auto, u mojoj ruci.
10:00
Amazing. Thank you.
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Zadivljujuće. Hvala vam.
10:03
(Applause)
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(Pljesak)
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