with Aditya Jain, Carol Lynn Alpert, & Calvin LeungMore Info
In this second part of Tom's podcast on quantum computing he looks at the strange world of quantum entanglement and the views of scientists and researchers working on quantum computers who where interviewed at a recent event, Nano Days with a Quantum Twist, which was held at the Boston Museum of Science.
TK: This week on Foresight Radio, part two of my podcast on Quantum Computing. In this episode, we’ll dive deeper into the realm of the quantum by looking at some of its more esoteric aspects, such as entanglement; the spooky property of quantum mechanics that even Einstein had difficulty in accepting. I’m your host Tom Koulopoulos, and Foresight Radio is brought to you by our good friends at Wasabi Technologies, the leader in the next generation of cloud-based data storage. You can learn more about them at Wasabi.com. Now, part two of my podcast on quantum computing. In our last episode on quantum computing with talked Bob Sutor at IBM. Bob gave us a bit of a background on what quantum computing is from his perspective. To get a better sense of quantum computing from the eyes of a scientist. I talked to Aditya Jain. Aditya is a PhD student at the Institute of Quantum Computing in Waterloo, Ontario. He’s originally from Kolkata, India. Aditya has been inspired by the technology of quantum computing and he describes it in pretty straight forward terms. Although, as you’ll come to understand, it is anything but straightforward. Here’s a bit of background on Aditya. Aditya: I think for me, it all started in undergrad. So, my undergrad, I was fortunate to land into a program which combines computer science and natural sciences. The thing that got me in quantum per se, was it’s like a neat combination of my favorite areas. It kind of neatly mixes computer science, physics, and math, all three areas. TK: One of the things about quantum computing that I'm sure you got asked repeatedly, by all of your friends, all of your family, is what is it? How do you make it simple and describe it to people who don’t have the background in engineering or in science and computers that you do. How do you simplify it, to its essence? Aditya: Let me just explain a very, very basic concept of computing, that is called a bit. A bit is nothing but two possibilities. A zero or a one, that’s a classical bit. We say a classical bit. A classical bit is allowed to exist in only one of these possibilities. For example, let’s say I gave you the information that a ball is either red or blue. Once I see the ball, it’s red and it’s going to stay red throughout, that’s a classical bit. Things change when you come into the quantum domain. You can be in a mix of these two possibilities at the same time, and these states do evolve. When you measure them, when you do some operations on them, these states can change. So the color of the ball is no longer a property of the ball. It changes. So that’s the fundamental difference, I would say. TK: How long did it take you? When you first started studying this, how did it take you to get to the point where you said “You know what? Now I understand it. I’m fluent in it.” If you think about the analogy being a language. If you learn a new language for a period of time you struggle, you have to translate it in your head. You have to think about what you’re saying, and one day, you wake up and suddenly think in that language. How long did it take you to get to that point, or are you at that point? Aditya: I think there is this a famous quote that nobody understand quantum mechanics. TK: [Laughter] It seems that way sometimes, right? Aditya: [Laughter] The reason behind this quote is like, for a lot of the classical physics era, everything just followed with intuition, and then at some point, you have to accept that intuition breaks down and you have to accept the experimental results, and work accordingly. Form a theory accordingly and because classical mechanics was breaking down at some small level, and you need to come up with new laws that go well with the experiments. So, that’s one of the challenging points of quantum mechanics. Your intuition doesn’t quite behave the same way, your regular intuition, but I would say once you spend a year, a year and half in the field, you go see in the labs - I’m a purist but if you see things happening in the lab, you kind of get more adjusted to it. So, I would say about a year of studying in the field would get you, somewhat convinced. TK: There are many different aspects of quantum mechanics that we find interesting and befuddling. One of the ones, that I think is the most amazing is this theory of entanglement. I believe, and I’m not a physics theorist, so you can correct me if I'm wrong. Probably, Einstein once said something about God not playing dice with the universe. He had a fundamental difficulty with things like entanglement and how those might work, and the fact that they exceed the speed of light was something that he had a difficulty with. What do you think Einstein would say today, if he could see what we’ve done, what you’re doing, with quantum computing. Aditya: So, first of all I want to clear this misconception. TK: Please. Aditya: We don’t really exceed the speed of light. We don’t communicate beyond the speed of light. TK: Okay. So, this is where things get really pretty weird. This notion of entanglement is one that you come across over and over again if you talked to anyone about quantum computing. In its simplest sense, entanglement is what happens when two objects that are at the quantum level tied together, behave in a way that is identical between those two objects. Now, the problem Einstein had with that, is that if these objects are separated, let’s say, about the distance of the universe, then how could they instantaneously have the same state. Now, keep in mind here, that when we say the same state, these objects are entangled, but we don’t know what state they’re in. They know, but it hasn’t yet been revealed to us. So, once we reveal the state of one quantum object, suddenly the other one has that identical state, and the misconception that Aditya is pointing out here, is that we believe that’s because somehow communication has exceeded the speed of light. But they’re not communicating, at least not in the classical sense. Here’s how Aditya describes quantum entanglement. Aditya: So, this is the no signaling principle or no communication beyond this faster than light principle, it still holds true. Even with entanglement, you cannot communicate faster than light. So, that is intact. We aren’t breaking that down. TK: Good. We’re safe there? Aditya: Yes. We are safe there. TK: Okay. [Laughter] Aditya: Coming to Einstein. Yes, there was this paper by John S. Bell, which is one of my favorite papers. TK: Yes. Aditya: There is a bit of history to it. So, Bell wasn’t as famous as Einstein, so people weren’t really believing him and then he came up with this really simple paper. Simple, I say in the sense, it’s easy to understand and very interpretable, there’s no rocket science there but, it kind of disapproves what Einstein was putting forward. Coming to Einstein’s belief, so there are – if I'm allowed - there are two notions here: one is reality, one non locality. So, reality basically means, as I was commenting, the property of the object is like it’s a property of the object. So, if I associate a color to a ball, it’s a property of the object. No matter what, it’s the property of the object. That’s reality. Coming to non-locality, it’s like if two people are far apart, they’re called non-local. So, it’s been proven in literature that the theory cannot be both local and realistic. Meaning, you cannot have like reality associated to objects and have locality at the same time. So, quantum mechanics, it has been shown via innumerable experiments at quantum mechanics. While it’s this one inequality, so there’s this – there are various inequalities, but there’s this famous Bell Inequality, which, if you have a local and realistic theory, should have some bound, let’s say should have a number - upper bound two. By upper bound, I mean the maximum value of some expression should be two but, if you use quantum mechanical resources, if you use entanglement, you can go up there two-to-two and they are able to do that. We have been shown via multiple experiments. TK: So, you’re probably scratching your heads as I am. Trying to figure out what this notion entanglement really means. The difficulty with quantum computing, which is pervasive in just about every aspect of it, is that we really don’t understand at its fundamental, at its core how it works. So, when Aditya talks about reality and non-locality, it sounds a little difficult and obtuse to follow, doesn’t it? Think of it this way. There are aspects of science, which we constantly have to disprove in order to prove new theories, new frameworks. We go back to the 1500’s when Ptolemy’s view of the geocentric solar system gave way to the Copernican view of the sun instead as the center of our solar system. You can liken that to what we’re going through today as we think about how physics works in the way that we understand it in the real world, what Aditya calls reality, and in this non localized world of quantum mechanics and entanglement. Here’s another approach to understanding Einstein point of view. This is Carol Lynn Alpert, who is the Co-Director for the Center of Integrated Quantum Materials at Harvard University. Carol: I think people don’t give Einstein enough credit because he was one of the founders of the quantum revolution. It was that group of scientist in the 1920’s and early 30’s, who really inaugurated the first quantum revolution. Einstein had some serious doubts about the quantum behavior like entanglement, which made sense, in the context of trying to find real reasons, real cause and effect, and that’s the goal of scientists everywhere, and it seemed unreasonable to him that one object could be entangled with another object across space, and that that connection was possible even beyond the speed of light, so that no contact could have occurred between those two objects. He kept feeling that the science wasn’t done, that there must be something that we haven’t yet discovered. But, ever since then we’ve been able to do more and more sophisticated experiments to show that quantum entanglement is real, and it isn’t explained by the science we had previously, but also that we can begin to harness those qualities. It is opening a very excited world for scientists and engineers to play in and we just don’t know what will come out at the other end. TK: What Carol refers to as the other end is something that we hear a great deal about, it’s the question of when will quantum computing be real? When we will start to use in place of classical computers or in a combination with classical computers? Here’s Aditya’s point of view on the timeline. Aditya: The next decade is the most exciting decade of the field, I would say. I think this is a very interesting decade for the field. If you want to really compare it, you know that transistors existed in the 1950’s and 1960’s. TK: Right. Aditya: They were of your room size. TK: Yes. Aditya: We are somewhat at that stage. You had these computers, they are in a very special environments, but at the same time, to the understanding so far, it’s okay, quantum computing won’t help you on everything. Your day to day computing does remain the same but, we are still in the process of exploring but there are a large set of problems which will give a huge speedup. [Wasabi Advertisement] TK: When you stop to think about it, if we were to go back to the dawn of the transistor and try to foresee all the ways in which it would change our lives, change our world, it was impossible back then, it is just as difficult as today to look forward and answer that same question for quantum computing. Where will it be used? What kinds of problems would it solve? But, there are some insights here and some directions. Here’s what Carol Lynn from Harvard, who we talked to earlier, had to say. Carol: Back in 1947 where Bardeen, Brattain and Shockley invented the transistor, no one quite knew what to do with it back then. We couldn’t really imagine laptops or smartphones or the worldwide internet in the early ’50s. Right now, we probably can’t imagine the full impact that the quantum revolution might have. TK: Here’s Calvin Leung, who is a graduate student at the MIT and an intern at SpaceX. Calvin was also one of the finalists who I interviewed at the Nano Days of the Quantum Leap competition at the Boston Museum of Science. Calvin: I think that the most exciting thing, for me personally, is the possibility of simulating really complicated quantum systems. There are processes out there, the Haber process is one of them, where you make fertilizer from ammonia. Energetically, it cost a lot of energy input in order to make fertilizer. If you’re going to do industrial farming on a global scale, you’ll need a lot of fertilizer. So, if you can somehow simulate the quantum mechanics of a reaction that turned ammonia into fertilizer and you can figure out some catalyst, some material that speeds up that process, makes it less energetically expensive, that would be enormous. That would be a huge benefit. Quantum simulation of molecules, and essentially just doing chemistry, that’s an extremely difficult process to do end to end. The way people do it now, there are certain approximations that you can take. When you make approximations, you don’t really capture the full picture. I think, one place where quantum computers can really have an outstanding – where they can really shine is using a quantum system to truly simulate another quantum system. It’s the only way to do it. TK: That’s a fascinating way to look at it. So, we are modeling - with quantum computing, we’re modeling the natural world in the way that we couldn’t with traditional computers. Calvin: Yes. TK: With binary computers, because it would take too long. But, we can model the natural world with the quantum computing. Calvin: Exactly. A lot of times, people frame this discussion with quantum computers in terms of power and how quantum mechanics gives you parallelism but, in this case, it is not even that. I mean, there are certain tasks for which quantum computers are worse [Unintelligible] than classical ones, but for this particular one, simulating a quantum system, the only way to do that is with another quantum system. This is something that Richard Feynman observed back in the ’80s that really launched this whole field of what if, in the future, we could string together some atoms in a lattice and make them into a computer of sorts, where you can simulate some other quantums? I think that’s fascinating. TK: Calvin mentioned Richard Feynman. You won’t get too far in any conversation about quantum computing without his name coming up. Feynman was one of the most influential physicists of the last century. He worked on everything from the atomic bomb to the Rogers Commission, which investigated the Space Shuttle Challenger disaster in the 1980’s. Along with all of his work in theoretical physics, Feynman was in fact the father of quantum computing, as we know it today. He wrote a paper in 1981 that was called Simulating Physics with Computers. In that paper, he talked about exactly what we’ve been discussing in these two podcasts, that a quantum computers do a marvelous job of simulating the real world, the biological world, the chemical world, which plasma computers simply cannot do, and if they can, it would take them millions or billions of years to come close to the kinds of equations that a quantum computer can take on. You often hear about folks like Heisenberg, Bohr, and Schrodinger when you hear about quantum mechanics. They were sort of the ones that laid the foundations, along with Einstein, for much of the theory but it was Feynman who ultimately made the connection between the quantum mechanics and quantum computing. If all this talk about entanglement and quantum mechanics and physicists is throwing you for a bit of a loop, don’t worry Calvin has a great way of putting this into a framework that makes it understandable. Calvin: One analogy I really like is when electricity was invented, people really didn’t have a sense for what this was good for or have any intuition for what electricity did or how it functioned but, now, everyone knows, if you don’t plug something into the wall, it’s not going to work, and if the connection is bad, it’s not going to work. TK: Calvin makes a great point because, look, at the end of the day, most of us don’t really know what voltage is or what watts or amps are. We understand the numbers and that you plug a 120 volt appliance in a 120 volt outlet, but do we really get what’s going on behind the scenes. How the electron is being transferred through the wires? Of course not. The same thing applies to quantum computing. We may not understand it, but it can still be extraordinarily valuable in how we go about our day to day. The last thing worth talking about when it comes to quantum computing and quantum mechanics, in general, is the level of understanding in education that supports this new field. I recall when I was first beginning to gain some interest in digital computing, there were no courses in school that taught you about computers. I learned on the job, if you will, by, quite literally, using a soldering iron and transistors. It’s tough to do that with quantum because it is steeped in such tremendous science that requires a whole new level of adeptness, instrumentation, and resources. So, I asked Carol Lynn, whom we spoke in earlier to talk about her work as Director of Strategic Projects at the Boston Museum of Science, and a little bit about the role that she sees museums and education play in building this new quantum workforce. Carol: As you might suspect, there is not very much teaching of quantum science and physics in K through 12. In fact, it’s only within the last couple of years that universities has begun to establish programs in quantum science and engineering. They’ve been buried inside other departments like physics, applied physics, engineering, [material] science. Now, it’s being recognized as a field. It’s a very, a very cross disciplinary field, and that means the people need training in many related disciplines. One of the things that science museums are very good at is free form experimentation with how do you communicate a difficult concept. What modalities, what visualizations, can you use? And that is important experimental work to happen before curriculum is built around these areas. TK: So, there you have it. Quantum computers are going to change the world or are they? The practical answer is that we just don’t know yet. In my last book, Revealing the Invisible, I talked about how John Vincent Atanasoff had designed the first digital computer on which the Electronic Numerical Integrator and Computer, also known as ENIAC was built in the 1950’s. At that time, the only real purpose of ENIAC was to figure out the trajectory of ballistic missile. Not much of a use-case and not one which you could expand easily into all the applications that we use computers today. Look, the reality is that quantum computing is going to evolve and, clearly, is going to change a lot of the way we think about computing. Will it replace plasma computers? From what I hear in everyone that I’ve talked to, likely not. At least not in the near term. However, it will open up the door to an entirely new way of thinking about computing, and how it helps us to model and simulate the natural world. That, in and of itself, might be a pretty incredible starting point. Where it goes from there? Your guess is as good as mine. However, one thing is clear, stepping into the future is going to require letting go of the past, and at some point, embracing this crazy, spooky, new world of quantum computing. To find out more about quantum computing, just check out the links on the Foresight Radio homepage at foresightradio.com. Thanks again to our sponsors for this episode of Foresight Radio - Wasabi. Take a look at how wasabi is changing the rules of the game for cloud storage at wasabi.com. Thank you for listening. If you enjoyed this podcast, please be sure to subscribe to Foresight Radio and to share in with your friends and your colleagues. This is Tom Koulopoulos, I look forward into joining you again soon for another episode of Foresight Radio. Where we explore the future of how we can live or play in the 21st century.