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How does a quantum computer work? · Technology Now

• MICHAEL BIRD Good morning to you, Sam. SAM JARRELL And good afternoon to you, Michael! MICHAEL BIRD If you could be in two places at once, where would you be and what would you do? SAM JARRELL I feel like I would probably be on vacation and also able to work at like the same time. Something like that. What about you? MICHAEL BIRD I think that's the only correct answer, Sam. I would be on a beach somewhere or on a mountain somewhere and also at work. And of course the reason I’m asking this is that we are doing an episode all about quantum computing and the ability to be in more than one place, or in this case, quantum state (more on that later) at once is one of the fundamental aspects of these computers. Buckle up, it’s going to be a slightly mad episode so I hope you’re ready. I’m Michael Bird SAM JARRELL I'm Sam Jarrell And welcome to Technology Now from HPE. MICHAEL BIRD Quantum computing has been around for a while, coming and going from the news as breakthroughs are made. Originally conceived in the early 1980s , it’s captured the minds of technologists, and the general public alike. SAM JARRELL Given that we don’t all have quantum computers at home, it feels like the technology hasn’t exactly moved quickly like it has with regular computers, right? MICHAEL BIRD Absolutely. Quantum computers are… a touch more complicated to build than a regular computer, in fact the 2025 Nobel Prize in Physics was actually awarded to three men for their work in the 1980s on superconducting quantum circuits which laid the foundation for quantum computing today. So, to find out more about quantum computing, and to lay a bit of a groundwork for what I am sure will be many more quantum computing episodes to come, I spoke with Dr Michaela Eichinger, a Product Solutions Physicist at Quantum Machines. SAM JARRELL But, before we chat to Michaela, you mentioned supeconducting quantum circuits earlier. Superconductors tend to need to be cooled to absolutely freezing temperatures so, I thought it would be interesting to look at how exactly we can do that. How do we create the coldest places in the universe right here, on earth? It’s time for… Technology Then SAM JARRELL So superconductors need to be cold right? In most cases, we’re talking liquid nitrogen levels of cold. But how cold can cold actually get? Michael, you’ve heard of absolute zero, right? MICHAEL BIRD Yeah, I'm trying to remember it from my GCSE physics. think it's minus 273 degrees centigrade. I don't know if that's in Fahrenheit, but cold. SAM JARRELL Do you know what it actually means? Like in physical terms, what does it mean for something to be at absolute zero? MICHAEL BIRD I think it's where particles stop moving. whether that's atoms or whatever, like the colder it gets, the less stuff moves. I think that's what it is. SAM JARRELL So, absolute zero is the coldest possible temperature – if you want to put a number on it, it would be negative 273.15 degrees celcius, negative 459.67 fahrenheit, or simply: zero kelvin. If you think of heat as just another form of energy, then at absolute zero, there’s no heat energy left at all. It still has a quality knowns as zero-point energy – a base level vibration in the atoms themselves but in terms of energy which can be removed to lower the temperature… there’s nothing left. Now, why do we care about this? Well this is an episode about quantum computers, and one of the biggest issues these computers face is that the quantum bits they need to work are inherently unstable. Cooling them down until they are close to absolute zero helps keep these quantum bits stable. Unfortunately, quantum computers need to be colder than outer space which clocks in at a toasty minus 270 celcius (that’s minus 455 fahrenheit). So how do we cool our quantum computer? Well, we use a dilution refrigerator – a device proposed back in the 1950s which mixes two isotopes of liquid helium called helium three, and helium four . The dilution refrigerator uses a quantum mechanical process called phase separation to cool things down where when the helium three is added to the helium four, it absorbs energy out of the helium four forcing the temperature to plummet. Because super cold helium will not freeze under normal conditions, we can cool it more and more in the dilution refrigerator until temperature drops to just 5-10 millikelvin at which point, our quantum computer is ready to go. MICHAEL BIRD An I thought I was smart by having my TV just controlled with one remote. That is next level smart Now, the super cooled components are just one part of a quantum computer so to find out more, I spoke with Dr Michaela Eichinger, a Product Solutions Physicist at Quantum Machines, and the first thing I wanted to know was simply, how did she get to whre she is today? MICHAELA EICHINGER So my background is in, you know, experimental physics. I did a PhD in so-called superconducting qubits. And then during my PhD I already was very exposed through friends, friends to the deep tech industry and community. And I got very interested to, you know, join a startup and learn more about product development. Business development and these kind of things. and now I get to basically sit exactly at this intersection between, you know, research and science and product and business development. MICHAEL BIRD quantum computing has always felt quite, um, theoretical. but are we saying it's now maybe moving from being theoretical to being something that is starting to have some practical applications? MICHAELA EICHINGER So maybe let's take this statement a little bit apart because yes, I think 30 years or 40 years ago, quantum computers or building um, devices based on the principles of quantum physics was very theoretical. And so the past two decades especially, um, many, many labs and companies around the world have been trying to build now a quantum computer. Then of course it's still this open question, when is it useful? So we're still at the very early stages of building large scale quantum processors, but we're seeing already very novel applications, especially when it comes to, um, exploring novel and new physics, for instance. MICHAEL BIRD Okay. Well. I think that leads us really nicely to try and, uh, do something nice and simple and explain quantum computing in, in under 15 minutes. This is written by my producer. Producer Harry is also a physicist. So, let's start with quantum mechanics 1-0-1 and define a few terms, if that's okay. MICHAELA EICHINGER Yes MICHAEL BIRD So let's start with a quantum computer. What is a quantum computer? MICHAELA EICHINGER So I would say it's a new species of compute. Um. It's a device that is built on the foundational principles of quantum mechanics. And because of that, it gives us very unique new capabilities of solving problems that we haven't solved before. MICHAEL BIRD Right. Okay. And, uh, you mentioned the phrase a qubit. What is a qubit? MICHAELA EICHINGER So the fundamental building blocks of such a quantum computer are so-called quantum bits or qubits. I really like, uh, the light switch analogy. So a classical bit can be on or off, zero or one, But a quantum bit is more like a dimmer switch where you have, of course, also on and off, but there are many, many states in between. So the quantum bit, um, can have all of these in between states. And we refer to this also as, um, the quantum bit being in superposition but this is very theoretical still. So what is a quantum bit? If we're talking about hardware and there, it gets actually very interesting because we have many, many systems in nature that can be a quantum bit, but we also manage to artificially engineer and build quantum bits. MICHAEL BIRD Um, I understand the principle of a traditional bit is, is either on or off. And so you can use that to make calculations or you can, you can do useful things with it, but I, I don't really understand how it would be useful to have something that could be on or off or an infinite, infinite number of positions between on or off. How can you actually do anything useful with that? MICHAELA EICHINGER Yeah, so if you think about a simple problem or how a classical computer works, right? You have all of these zeros and one, these classical bits switching back and forth, and it's all a more serial process of finding, um. The solution to a problem. And of course we have, you know, GPUs where we can do all of many of these processes in parallel, but intrinsically it's still, you know, serial processes that try to find, um, a solution to a problem. And a quantum computer is fundamentally different because you can basically bring a quantum. In this superposition of, of many, many states and then there is one other, um, characteristic that matters a lot is that you can also entangle multiple qubits. What is entanglement? It just means that you can have multiple qubits and their state can be correlated to each other. you cannot find this in classical bits, but also this correlation across, you know, many distances give you a novel way of, um, thinking also differently about a problem and utilizing this for a computation. MICHAEL BIRD Okay. My head is slightly hurting, but that's okay. I, I, I knew this was gonna happen. what problems are, like, are good to, to use a quantum computer for? MICHAELA EICHINGER Yes. So I think if we think about nature and the principles that, you know, everything is spilled up on, so nature is fundamentally quantum mechanical, so of course. It's just natural. If you wanna simulate nature simulate, um, molecules, model new, materials, new drugs that we do this with the quantum computer because the quantum computer is fundamentally also built, um, on the principles of, of quantum mechanics. MICHAEL BIRD And can you give any practical examples of, of what a com, uh, quantum computer would be much better, much faster, give you better results than a traditional computer? MICHAELA EICHINGER we have novel materials, so-called superconductors. Which, um, allow you to have an electrical current that runs without, um, resistance. Hmm. So it can run in like infinite, um, as soon as you, you know, have it running. And unfortunately, these properties only, um, pop up below certain temperatures. So right now we need to cool these metals to below their so-called critical temperature, um, to exhibit this, these superconducting properties. So there is the hunt for superconductors at room temperature, but this is a very hard physics problem, and quantum computers can actually help to find materials and material combinations that might exhibit this, um, this property at room temperature. And then it really revolutionizes everything, you know, that utilizes metals and that could benefit from, from superconductors, MICHAEL BIRD These sorts, the, the sort of problem we talk about sounds like the sort of problems that we say that AI is good at. obviously AI uses traditional computing, but it's approaching problems in what sounds like a similar-ish way to a quantum computer, how do those two relate? Do they compete? MICHAELA EICHINGER They, they actually don't compete. Good. So first of all, AI is the, is still built on traditional compute, right? And what is very important and often misunderstood is that we actually need a lot of classical compute for the quantum computer. So these days, we actually already also co-locating our quantum computers in data centers and HPC centers because we need classical compute and AI to actually operate our quantum computer. Um, so they are basically, you know, um, in, it's an integrated architecture that we're building and we're working towards what we call a quantum supercomputer, actually. So the big goal is actually a quantum supercomputer where you have AI and quantum working hand in hand amplifying each other. And it can go in both ways. It's, you know, AI for quantum and quantum for ai, you will find use cases for, for both sides. So they work in tandem. MICHAEL BIRD So how do you actually build a quantum computer? 'cause I think this is, this is the thing that, um, I think it's maybe the most interesting part of this conversation because we've had conversations about quantum and quantum computers on the shape before, and it, and again, it was sort of, it was quite theoretical. Mm-hmm. But actually I'd love to practically understand. MICHAELA EICHINGER What, what are the building blocks? it's an excellent question and the great thing actually there is. There are multiple correct answers to this questions because there are multiple ways how to build a quantum computer, and it goes back to having these multiple options of how to realize a quantum bit. So there, for instance, in nature, atoms and ions, they already can be utilized as a quantum bit. So these types of quantum computers. Are built, they, they look, you know, to me they look quite messy because you walk into a room and you see a lot of optical components standing on, you know, mirrors and lenses and lasers. So it's huge infrastructure to trap multiple atoms and then control them via, um, laser beam and on the other hand, which is maybe natural for, for many of the semiconductor industry, and also more natural to me, is that you really have a silicon chip. You, um, make electrical circuits on it using semiconductor fabrication technologies, but then you need to cool this chip to very cold temperatures, so much colder than outer space. And so you need this infrastructure to cool it. So, um, it's just a, it looks like a big, big box, um, that hangs often from the ceiling, but it actually allows you to put the chip at the very bottom and have it cool to, um, below minus 273 degrees Celsius. And this is just one part of the story because. We have the chip, but then we need to operate this chip, right? Just having quantum bits on a chip doesn't give you a computer. So we will have many signal, signal lines and cables going down to this chip. And then at room temperature, we will have boxes that generate signals that go down to this chip and back up. And that actually then perform and, um, apply an algorithm, for instance. MICHAEL BIRD there are quantum computers that exist today that you can do something with. They're not just theoretical, they're, they're, they're actual things. MICHAELA EICHINGER They are actual things, and you will find them in many countries and in many companies and in many labs, and typically you can visit them quite easily as well, or even access them, um, online these days. MICHAEL BIRD what are the challenges with scaling it? Can you just, you know, put some more chips, get some more hanging baskets? MICHAELA EICHINGER That will be the great thing, and we're doing that. But the problem is that intrinsically, a quantum bit is a very fragile system and it's very sensitive to its environment. So on one hand, actually we would not like to, you know, on one hand we would like to isolate the quantum bit as much as possible, but then there is this trade off because we wanna do control and computation with it. So we need to connect to it. So, um, but that of course also induces error. It can destroy the quantum state. So the problem is, um, to actually scale to many, many qubits and keep the system alive. Um, so this is one big issue and the more you scale, you know, the more engineering challenges that you have. MICHAEL BIRD and how big are the computers, the quantum computers at the moment in terms of qubit? MICHAELA EICHINGER So there is a variation, for instance, on superconducting qubits, we are in the range between 103 hundred. And then we have neutral atom computers where, um, we trap, you know, neutral atoms and there we are actually already in the thousands, but they, they have different kind of capabilities and connectivity. Um, but so in general, we cannot say that, you know, one modality is winning over the other because they all have currently their advantages and disadvantages. MICHAEL BIRD So from a practical sense, I guess from an organizational perspective, why is quantum computing something that organizations should, should care about? MICHAELA EICHINGER I think this goes back to it being a new species or a new flavor of compute. any kind of, um, company that actually uses high performance. I think, um, will benefit in the future from working also with quantum computers because they're already u like trying to solve problems in a space where quantum computers will be naturally good at. MICHAEL BIRD And I've, I've been told like, it's not likely you'll be, uh, you know, doing word processing on a, on a quantum computer. 'cause it's not great at that. It's like playing to playing to its strengths. MICHAELA EICHINGER Exactly. So you will also not, you know, open your email using a quantum computer MICHAEL BIRD fire up my quantum computer in the morning, open up my emails. Yeah. MICHAELA EICHINGER Maybe the email is there, maybe it isn't. MICHAEL BIRD Yeah. so would a quantum computer be integrated into a, into an existing system? MICHAELA EICHINGER I think that's exactly the right term. We're also now in the quantum space talk about classical compute as an accelerator for quantum compute. Okay. Um, and that's why we will see this cointegration more and more MICHAEL BIRD Interesting. Would you run AI on a quantum computer? Is that an application that would be great for it? MICHAELA EICHINGER So there is a field that is, um, explored, which is called quantum machine learning. So that is actually running AI on a quantum computer. I think this is also still, it's a bit, um, controversial as well, I would say in the community. But there is heavy, you know, investment in exploring this avenue. MICHAEL BIRD Okay, so we, we ask, we ask all of our guests when we, that we interview about quantum computing this, what do you see as the timeline for a, a quantum computer? Like are we in a bit of a quantums armor race, so to speak? MICHAELA EICHINGER We are definitely in a quantums arm race. Um, there, every country or so many countries now have a n National Quantum Initiative. There is lots of government funding, um, and private funding has been on the rise for this field as well. And what I've been seeing as well is export regulations even on smaller quantum computing systems. So there is big, national and global interest in building a large scale quantum supercomputer and the timelines. I think everybody's trying to, you know. Get really something useful done by the end of this decade. MICHAEL BIRD makes you most excited about the possibilities of of a quantum computer? So because I'm an experimental physicist by training, I'm very excited about, you know, pushing the field of physics forward and discovering really new materials, I think, and, um, high temperature superconductors. Yeah. McKay, it's been absolutely fascinating chance to you. Thank you so much for coming onto to technology now. MICHAELA EICHINGER Thanks for the invite. I really, um, enjoyed it as well. Thank you so much. SAM JARRELL when anyone talks about quantum, it is one of those things that I feel like goes way way over my head, even when they're trying to bring it down to my level. But I do appreciate that you guys, you know, had sort of a discussion around like, how do even build these things? And what it seems to me is like, temperature seems to be the piece that seems to like come back to everything here. And I find it fascinating too, that like, we need the quantum computers to be incredibly cold, but then quantum could help us discover room temperature superconductors. And I feel as though it's all kind of like cyclical to some degree. And that could be quite nice. Like I imagine energy efficiency and transportation computing, everything will look different if this becomes real. MICHAEL BIRD I bet Quantum Labs have got really good ice cream, because you're right, everything's all about keeping stuff cool, isn't it? I also just struggle to wrap my head around it, but I did find the analogy of the dimmer switch to be quite helpful to wrap my head around what is meant by a qubit. that is, like a normal bit is just like a normal light switch, on or off, one or a zero whereas a qubit is a dimmer switch, so... and that is what they call a superposition, so it could be 1, 0, or any number in between… it’s quite fascinating. But it's also quite daunting, I think, as a topic to sort of wrap your head around. we're to be doing some more episodes on quantum computers, I think. What I also found fascinating was that quantum computers aren't just theoretical, they're actual things that exist. And I saw some photos of quantum computers from some other companies. And yeah, I think I described it into as a hanging basket. And I think that's what it looks like to me. It's like this big, almost like dustbin hanging from the ceiling with all these wires coming out of it. I'm guessing to keep it very, very cool and for the connectivity. But she said, yeah, they exist today and they can be accessed online. So there are cloud quantum computers. SAM JARRELL Yeah, that's crazy to me. And does that mean like what I could go to like a site for them and then I'd probably not leverage it. But I guess maybe you can watch people leveraging them. MICHAEL BIRD She talked about them being hand in hand with classical computing, amplifying each other and sort of refer to it as an accelerator for classical computing, which I think, again, I think is quite fascinating. And I think when we interviewed Antonio, Antonio Neri back in December, think he mentioned that, know, Consum computers being an accelerator for a classical computer. SAM JARRELL Yeah, he did. I think that whenever we talk about these individual pieces, it always kind of also comes back to eventually them all sort of working together, like her mentioning that they need to be located in HPC data centers, because it classical compute, but then also to accelerate it, but then it needs classical AI to operate. It feels like it's all kind of a glimpse into a future where these things are not separate, but they're all part of one giant, powerful system. MICHAEL BIRD I agree with you on that. Now, Sam, earlier on, you mentioned us not having quantum computers at home yet. And actually, that was something I wanted to ask Michaela. Given the advances we've seen in quantum computing over the past few years, will we ever have quantum laptops at home? MICHAELA EISINGER So quantum laptop, probably not in the near future. Um, just because we also don't have high performance, you know, computers, super computers at home. It's very big and bulky. Um, so I don't see in the near future this being, you know, collapsed to a little laptop and it's probably also not necessary. Um, but then the quantum cloud, actually we do have a quantum cloud because many quantum processors can be accessed, um, via, via the cloud these days. to also push the research and push and accelerate the progress on these devices. SAM JARRELL Okay that brings us to the end of Technology Now for this week. Thank you to our guest, Dr Michaela Eichinger, And of course, to our listeners. Thank you so much for joining us. MICHAEL BIRD If you’ve enjoyed this episode, please do let us know – rate and review us wherever you listen to episodes and if you want to get in contact with us, send us an email to technology now AT hpe.com man there are so many subject line options subject line superposition or dimmer switch both those are fine and of course don't forget to subscribe so you can listen first every week Technology Now is hosted by Sam Jarrell and myself, Michael Bird This episode was produced by Harry Lampert and Izzie Clarke with production support from Alysha Kempson-Taylor, Beckie Bird, Alissa Mitry, and Renee Edwards. Our theme music was composed by Greg Hooper. SAM JARRELL Our social editorial team is Rebecca Wissinger, Judy-Anne Goldman and Jacqueline Green and our social media designers are Alejandra Garcia, and Ambar Maldonado. MICHAEL BIRD Technology Now is a Fresh Air Production for Hewlett Packard Enterprise. (and) we’ll see you next week. Cheers! SAM JARRELL Bye y’all