A beginner’s guide to quantum computing | Shohini Ghose

A beginner’s guide to quantum computing | Shohini Ghose


Let’s play a game. Imagine that you are in Las Vegas, in a casino, and you decide to play a game
on one of the casino’s computers, just like you might play
solitaire or chess. The computer can make moves
in the game, just like a human player. This is a coin game. It starts with a coin showing heads, and the computer will play first. It can choose to flip the coin or not, but you don’t get to see the outcome. Next, it’s your turn. You can also choose
to flip the coin or not, and your move will not be revealed
to your opponent, the computer. Finally, the computer plays again,
and can flip the coin or not, and after these three rounds, the coin is revealed, and if it is heads, the computer wins, if it’s tails, you win. So it’s a pretty simple game, and if everybody plays honestly,
and the coin is fair, then you have a 50 percent chance
of winning this game. And to confirm that, I asked my students to play
this game on our computers, and after many, many tries, their winning rate ended up
being 50 percent, or close to 50 percent, as expected. Sounds like a boring game, right? But what if you could play this game
on a quantum computer? Now, Las Vegas casinos
do not have quantum computers, as far as I know, but IBM has built
a working quantum computer. Here it is. But what is a quantum computer? Well, quantum physics describes the behavior of atoms
and fundamental particles, like electrons and photons. So a quantum computer operates by controlling the behavior
of these particles, but in a way that is completely different
from our regular computers. So a quantum computer
is not just a more powerful version of our current computers, just like a light bulb
is not a more powerful candle. You cannot build a light bulb
by building better and better candles. A light bulb is a different technology, based on deeper scientific understanding. Similarly, a quantum computer
is a new kind of device, based on the science of quantum physics, and just like a light bulb
transformed society, quantum computers
have the potential to impact so many aspects of our lives, including our security needs,
our health care and even the internet. So companies all around the world
are working to build these devices, and to see what
the excitement is all about, let’s play our game on a quantum computer. So I can log into IBM’s
quantum computer from right here, which means I can play the game remotely, and so can you. To make this happen, you may remember
getting an email ahead of time, from TED, asking you whether you would choose
to flip the coin or not, if you played the game. Well, actually, we asked you to choose
between a circle or a square. You didn’t know it, but your choice
of circle meant “flip the coin,” and your choice of square
was “don’t flip.” We received 372 responses. Thank you. That means we can play 372 games
against the quantum computer using your choices. And it’s a pretty fast game to play, so I can show you the results right here. Unfortunately, you didn’t do very well. (Laughter) The quantum computer won
almost every game. It lost a few only because
of operational errors in the computer. (Laughter) So how did it achieve
this amazing winning streak? It seems like magic or cheating, but actually, it’s just
quantum physics in action. Here’s how it works. A regular computer simulates
heads or tails of a coin as a bit, a zero or a one, or a current flipping on and off
inside your computer chip. A quantum computer
is completely different. A quantum bit has a more fluid,
nonbinary identity. It can exist in a superposition,
or a combination of zero and one, with some probability of being zero
and some probability of being one. In other words,
its identity is on a spectrum. For example, it could have
a 70 percent chance of being zero and a 30 percent chance of being one or 80-20 or 60-40. The possibilities are endless. The key idea here is that we have to give up
on precise values of zero and one and allow for some uncertainty. So during the game, the quantum computer creates
this fluid combination of heads and tails, zero and one, so that no matter what the player does, flip or no flip, the superposition remains intact. It’s kind of like stirring
a mixture of two fluids. Whether or not you stir,
the fluids remain in a mixture, but in its final move, the quantum computer
can unmix the zero and one, perfectly recovering heads
so that you lose every time. (Laughter) If you think this is all a bit weird,
you are absolutely right. Regular coins do not exist
in combinations of heads and tails. We do not experience
this fluid quantum reality in our everyday lives. So if you are confused by quantum, don’t worry, you’re getting it. (Laughter) But even though we don’t experience
quantum strangeness, we can see its very real
effects in action. You’ve seen the data for yourself. The quantum computer won because it harnessed
superposition and uncertainty, and these quantum properties are powerful, not just to win coin games, but also to build
future quantum technologies. So let me give you three examples
of potential applications that could change our lives. First of all, quantum uncertainty
could be used to create private keys for encrypting messages
sent from one location to another so that hackers could not
secretly copy the key perfectly, because of quantum uncertainty. They would have to break
the laws of quantum physics to hack the key. So this kind of unbreakable encryption
is already being tested by banks and other institutions worldwide. Today, we use more than 17 billion
connected devices globally. Just imagine the impact quantum encryption
could have in the future. Secondly, quantum technologies could also
transform health care and medicine. For example, the design and analysis
of molecules for drug development is a challenging problem today, and that’s because
exactly describing and calculating all of the quantum properties
of all the atoms in the molecule is a computationally difficult task,
even for our supercomputers. But a quantum computer could do better, because it operates using
the same quantum properties as the molecule it’s trying to simulate. So future large-scale quantum
simulations for drug development could perhaps lead to treatments
for diseases like Alzheimer’s, which affects thousands of lives. And thirdly, my favorite
quantum application is teleportation of information
from one location to another without physically transmitting
the information. Sounds like sci-fi, but it is possible, because these fluid identities
of the quantum particles can get entangled across space and time in such a way that when you change
something about one particle, it can impact the other, and that creates
a channel for teleportation. It’s already been demonstrated
in research labs and could be part
of a future quantum internet. We don’t have such a network as yet, but my team is working
on these possibilities, by simulating a quantum network
on a quantum computer. So we have designed and implemented
some interesting new protocols such as teleportation
among different users in the network and efficient data transmission and even secure voting. So it’s a lot of fun for me,
being a quantum physicist. I highly recommend it. (Laughter) We get to be explorers
in a quantum wonderland. Who knows what applications
we will discover next. We must tread carefully and responsibly as we build our quantum future. And for me, personally, I don’t see quantum physics as a tool
just to build quantum computers. I see quantum computers as a way
for us to probe the mysteries of nature and reveal more about this hidden world
outside of our experiences. How amazing that we humans, with our relatively limited
access to the universe, can still see far beyond our horizons just using our imagination
and our ingenuity. And the universe rewards us by showing us how incredibly
interesting and surprising it is. The future is fundamentally uncertain, and to me, that is certainly exciting. Thank you. (Applause)

Danny Hutson

100 thoughts on “A beginner’s guide to quantum computing | Shohini Ghose

  1. Getting into quantum physics is, I believe, the closest natural beings can get to the supernatural realm. Its crazy. And considering where our world is today, while it is great technology, it is all the more dangerous.

  2. Good for the TED, but not tech at all. That kind of information should be technical. IBM videos is really better at that )

  3. Is there anyone in the comment section who understood how the coin game is won by the quantum computer?
    Is there anyone understood anything from this video?

  4. I still don't understand how the game work. With the explanation in this video, it seems that the player, which has the final move, is always win by simply flip the coin to Head all the time. She did successfully provide Quantum information in term of its spirit at the end, but not so well throughout the speech in aspect of technical.

  5. Possibilities are limitless.
    Medicine – Cured a lot of diseases, new era of good, healthy drugs controlled by gov. More happiness Longer life span.
    New materials -> development of new technologies – > new methods of production -> more new tech -> new jobs
    BBB or Bye Bye Byrocracy -> saved a lot of time, instant administrative regulation -> even more happiness. Everything you want is INSTA done.
    Security A word Hacker becomes historical term -> No free downloads.
    Math Solving some math problems -> New tech and all over again.

    Oh damn, it's 2019…

  6. You can do the coin thing with regular computers as well! Cause in the first place, the computer here is allowed to know whether I finally pick head or tail…. And then it needs a simple NOT gate to turn the result different than what I chose! Done and dusted

    Why even explaining quantum computer's functionality with this example! Shouldn't they have gone with something more sensible?!

  7. wow….to be zero or not to be zero….turns into being zero as well as not zero…quantum physics will alwas crack my head 😉

  8. Madam, I am from India.. What a nice and almost easy explanation you have given , though Quantum Physics is not an easy topic…

  9. Very nice presentation about something that interested me nowadays as an engineer …. can you tell me please what was the algorithm used to resolve the coin game you presented or where I can find something written about it …. just to have an example how the quantum computer resolve it !! Thanks a lot .

  10. definitely a very beginners guide…A quantum computer can break the encryption because thats what they are also designed to do….if you make it we can break it..sorry

  11. They will be trying to teleport rats next, and make synths. The future definitely is uncertain but not for you ya cheeky cow 😅

  12. I need one of these quantum cheaters for the lottery next week. Or as the quantum professors say: Shut up and calculate.

  13. You got it, if you realised you're not supposed to "get it" using your native senses, reasoning and scientific methodology.
    You're supposed to let your imagination take over and create a new reality, which you will then accept, because THEY said it works, not because you "get it".

    But then, you WILL get it, because it will become "common sense", which few people will really think about because it will be OBVIOUS.
    Eventually, you won't even try to "get" anything; you will just trust THEM.

    Does that sound like it's already happening, even without so-called "quantum computing"???
    Pray for everybody, especially our children who are going to have to wear all of this in the name of "education"!!!

  14. A total nonsense use case for this. People who speak about this do not have a clue about the topic in-depth. Just jargon speaker.

  15. The way this is explained, it seems quantum computers could solve the classic problem of 'what came first, chicken or the egg'

    Not joking but mocking the explanation of computation here.

  16. Im in IT and I love standard computers because you tell them what to do, always! Once you start letting computers think for themselves? George Orwells predictions come to mind.

  17. If the computer controls the outcome is IS cheating.

    It can also not know my encryption password to my data if the unlocking mechanism software is not rewritten to be in a undecided superposition state.

  18. This quantum computing stuff is compete nonsense and it didn't even calculate anything..
    The "computer" gets to peek at the answer before it produces it.

  19. Beginners guide? First example; the coin game, makes it possible for the coin to be placed on its side. (Fine) So the computer basically wins all the time. Good news for casino's, in the example. But where is the good in this for the humans. Next example healthcare [drugs], and we all know about the power of the pharmaceutical industrie. And the 'good' some of these have done [oxycodone just one of the many examples]. A next example is with banking, and we all know banks can be trusted. Everything has good and bad properties, I don't see the use in the potential good if it also gives the potential bad/dangers. Finishing it of that it is exciting times for her because she earns her 'good' money from these 'excellent' developments for humanity.
    First thing that pops to mind is; that a quick fix is hardly ever a good fix!!! How is this better for humanity and society? It is like the coin on its side. Massive leaps forward and at the same time extreem leaps backwards. Guess how it will be divided between humanity and a society of have's and have not's!

  20. To all the people who are crying "I don't get it" Neil Bohr once said "If quantum physics didn't profoundly shocked you, you didn't quite understand it". On a somber note, some concepts can't be explained in 10 mins.

  21. The problem with this technology is that will become so dependent on it that we will become the idiots and it will become the intelligence

  22. It sounds like a quantum Ponzi Scheme. I would rather take my chances with a traditional computers because they deal in precise values. Sorry no fluid combinations. Sounds like skynet and the Terminator (AI and consciousness). Let a computer decide for itself and throw randomness into the equation? Thanks but no thanks. How about you tell us what the quantum computer is made of, seeing there is one already developed.

  23. Amazing, quantas themselves , defined as particles sometimes defined as wave, their mass is zero, another time their mass can be calculated, really strange, when we step out of classic physics, the idea of uncertainty is more and more clear

  24. Let's hope she and her team don't fail as much as she did here at explaining the quantum computing on that game example. Totally useless 10 mins. Somehow with pretty high probability I knew it will end like this…I must be quantum oracle. Yes I knew it and I watched till the end only to make sure 😀

  25. I see quantum computers taking over humans and the computers will be making decisions instead of us. This is most likely what Elon musk is warning us about. Moral of the story: when Quantum computers are fully functional…run for your life !!!

  26. Quantum computing: when computers are able to taste the glory of winning, and use your misunderstanding of its behavior as a cover.
    See, the only reason why it is within spectrum is because human could only perceive a fraction of the end result but declare it as a whole. In other words, you've been played by your own perception.

  27. so basically quantum computer guesses the algorithm as there is no such thing as "random" in computing. There are "close to random" or "close enough for a human" but it is never random. So for us this is between 1 and 0 but for a computer its still 1 or 0 just with a whole algorithm that led to it?

  28. Typical Clickbait video. She didn't utter a word that is written in the description. That is THE EXPLANATION. not the applications

  29. Non-binary (wink!)… In a spectrum (wink!)… I see what you are trying to do there, but your pandering analogies fall apart because at the end everything collapses to one of two unique states.

  30. দেখে খুব ভালো লাগলো যে একজন বাঙালির মূখে Explanation টা শুনে ।। 😊

  31. I've been watching so many videos on quantum computers and still don't understand it. I understand the whole "it's not 0 or 1, it's both" thing but I get lost after that.

  32. Comments section is soo bitter and blaming the well-qualified speaker for not knowing what she’s talking about

    But my question is, who
    wrote the damn video title?

  33. could you not get a male expert to present it…the ones that are actually building the science and technology for this?

  34. In a nutshell, it's so complicated that you should not tell it to anybody within 10 minutes..
    The only part you will get is that it's not binary..

  35. I didn't get an example with a coin. Whats the point? I can manage a 100% success rate on my core i-7 without any quantum computer.

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