Magic Quantum Physics


“I’m a physicist, but I’m also a swing dancer,” said Krister Shalm, a postdoctoral research fellow at the University of Waterloo’s Institute of Quantum Computing. He introduced himself and set off 15 minutes of fast-paced action explaining his work with quantum physics in increasingly accessible and unusual ways. He capped off his talk by bringing out a band for a global swing dance number.


I’m a physicist, but I’m also a swing dancer. I do a type of swing dancing called Lindy Hop and I’d like to tell you about something that happened to me a few months ago. My wife while we’re in Thailand, we met up with a group of Lindy Hoppers and we want our swing dancing.

It’s agree at time but i’ll never forget this one dance that I had see my partner she didn’t speak any English at all and I didn’t speak any Thai. And yet we had this incredible dance. This is one of the things are love most about swing dancing. This partnered connection the fact that I could go to you almost any city in the world, not know the language any a find someone that I could share an experience through dance with.


I feel that dance can transcend words and allow people to communicate and different ways, now when I’m not leave the hopping my day job is a physicist and as a physicist what we’re trying to do is learned what are the rules the govern the world around us. How does the world work, and we find incredible is you only need a few simple fundamental principles explain most of the things that we ever experience. Take for example gravity, gravity is the force that causes and apple to fall to the ground. It’s also the same force that keeps the earth in orbit around the sun. All of the physics all of the rules that govern the things that we’d normally experienced we call this classical physics, but if we were instead to take ourselves and shrink all the way down to the smallest things like Adam’s you’d find that the rules are completely different, this is the quantum world and this is what I study and in particular what I study is a type of partnered dance that happens at the quantum level.


In my lab regulars I take the smallest chunks of light we call them photons and I bring them together and I need to know when they become partners, I might do this become connected in a powerful way in fact it’s the strongest connection that physics allowance. And what’s incredible is they don’t have to be next to each other to remain partners I could take them to you opposite ends of the universe and no matter what it did to this one at this one they would still remain correlated.


Einstein he called this spooky action at a distance.

I’d prefer to call it partner dancing at a distance. So this idea of entanglement is really difficult to explain because we don’t have anything and our everyday experiences are ones that match it, I can’t say ten with is like this because they’re is no this that we experience sometimes it seems like magic, fortunately I have a magician backstage who specializes in using magic to explain complex ideas he’s gonna come out and do a trick that’s going to kill a straight just what I mean when I talk about surprising correlations so join me in welcoming to the stage magician extraordinaire Dan Trommater.



Indeed the world argument quantum mechanics is so tiny and is so unlike our norden ordinary everyday experience that it does seem like magic and I understand there’s a couple folks who’ve agreed to come up and help me actually do a piece of magic illustrate this would be charming as I shuffle the cards they adhere very tightly catalog part classical physics they had no choice but in a moment of bring out a device that will allow us to transcend those laws.


Hello Don and Ivan thanks for helping now for the sake of yes indeed for the sake of time will just use about a half of the deck of cards uh… in order to demonstrate quantum entanglement at this point they exist firmly in the realm of classical physics I have a device that local our strength and a lot of classical physics and entered the realm apart the mechanics of it picked up krister slab at the institute for quantum computing ladies and gentlemen I present to you the quantum entanglement you get my honest about the world to love that have so hot fire refiners science at this point these cards are intent on so when I deal them into two piles one for each don and I dint even on separating them by a bit of a distance they still maintain entangled now guilty to be mixing your cards in a particular way out demonstrate how you do that you pick them up and give them one at a time as they come off the top into a small file these camps at some point you’ll decide to stop when you’ve done that you’ll turn everything in your hands over played onto the pile despite everything back up into your hand and you’ll do that again peeling them as they come eventually you’ll stop don’t turn over and septa does this make sense okay so please take your files given face uh… just as they come into a little time at some point of the slide the stop gap with everything in your hands set it down and continued fantastic you do that at three times now at this point their key to making a different decisions sometimes don’t feel in just a few cards Ivan human few more before eclipse this law and up producing a situation where in some of the card to face up some face down fantastic and yet if the laws of quantum mechanics apply they are still contain no kind of surprising correlation will take place let’s check the top card of each part top part of this bio the black cat a part of this car the red seven krister tells me this happens in the lab that sometimes you have to do a bit of a flip saw flip this pile up in the check now they’re both black tens.


This could be a coincidence so let’s check the next year the next top two cards black aces once they stopped once they found and yep they’re both red nines two black eights, two black queens two read tens two black sixes black fives [applause] red eights read fives black threes red Queens and those two red sevens and back this quantum entanglement.

Thank you very much, thank you very much, …

thank you Dan …


So what Dan did with these card tricks if you showed us that you can go the cards work independently shuffle they still remain correlated this gives you a flavor for what we do in the lab with entanglement when I intend to photons, they actually have correlations there even stronger then went down to it anti institute for quantum computing return to figure out ways to use these new rules a physics these quantum laws ideas like contentment developed the future generations of technology, for example take information security when you go on line into take your credit card over and you buy something you have to encrypt that information select unprotected at turns out in the future entanglement is going to play an important role with our type of communications that will carry out you can also use these new laws of physics to build a super fast computer we call it a quantum computer.


A quantum computer is so powerful but I’d like to actually give you an example of of a problem we can solve much faster than when a regular computer can take for example factoring factoring is something that many of us learning great school and then promptly forget so I’ll refresh your memories about how it works take the number fifteen it’s factors are 5 and 3 five times three is fifteen take twenty one it’s factors are seven and three seven times three is twenty one now if I were to give you a big number singer thousand digits long and I choose this correctly it would take all the computers in the world longer that the age of the universe and they still wouldn’t be of the factor appointed computer could do it in under a day this idea the speed up uh… it’s it’s exponential and just to help illustrate this idea of exponential speed-up I’d like to do a little demonstration with you. So I’m going to use this chessboard, and this bold and the nabs what we’re going to do is we’re going to play at the little game with this chessboard what’s going to happen is distrust for here has sixty-four squares and we’re going to be double the number of smarter dumber and then so we place on each square so in the first where I’m going to put and I’m gonna put two on the next one and then I’ll put for on the next one and we can continue this game I think you know put eight and then sixteen thirty two sixty four in seoul and if we wait here long enough, by the time I got to the sixty fourth square I would need to be bull of and ends the size of the birth just to put on that square wouldn’t we’re trying to build equal time computer what we’re doing is we’re just taking pairs of entangled particles but we take many different particles I mean tangle than and week choreography is very complex dance thus choreography what happens is every time we had a nude dance partner we bring another quantum particle in we actually the power of our computer it would be like adding of sixty-fifth square onto this transport and then now what you get is unique to bowls of and the numbers the size of the earth just a thought well that’s the power of exponential sp the computers better based on quantum mechanics but I have in my lab right now we’re we’re in this kind of region rate here this bottom corner of the chess board. We can do things like factor fifteen and twenty-one protection paper just recently out on someone doctrine twenty-one where we want to get is over to here because then we can start solving problems at our regular computer can’t and there’s going to be some advances in materials science breakthroughs that we have to carry on in order to achieve this but I believe this future is very bright for quantum technologies I think we’re actually at the beginning of a quantum revolution.


And so far I’ve been talking a lot about these ideas of quantum mechanics in how entanglement is like a partner dance, but at this time I’d actually like to dance for you. Now I need some help for this so I’d like to invite to the stage out one of my favorite bands of Roberta hunt and the gents as well as some lady hopping friends of mine we’re going to help me illustrator all of these ideas we’ve just talked about. Entanglement as a partner dance how you can use it to build an exponentially fast computer and so on and each dancer that you see is going to be a photon that will be entangle now of course we can actually use the answers to till the quantum computer my lab would be even more fun than it is but this I think dance is a very powerful way to illustrate these ideas and to communicate them but we ran into a problem you see entanglement is so big so powerful there’s no way that we just contain on the stage or even in this large venue here so we did is we were now regard almost five hundred dancers from thirty six cities around the world that have come together just to help illustrate this idea of quantum entanglement.




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