Transcript | Quantum Clocks, Sensors and, of course, Computing— with Infleqtion

Quantum information science just might have commercial impact before quantum computing achieves error correction. All sorts of vertical industries will be able to take advantage of quantum clocks and sensors, enabling better navigation and even seeing through miles of solid earth.

Find out about these amazing devices and what we expect from cold-atom computers in this episode of The Post-Quantum World. I’m your host, Konstantinos Karagiannis. I lead Quantum Computing Services at Protiviti, where we’re helping companies prepare for the benefits and threats of this exploding field. I hope you’ll join each episode as we explore the technology and business impacts of this post-quantum era.

Our guest today is the VP and chief quantum advocate at Infleqtion. He’s also the author of Dancing With Qubits and Dancing With Python. Dr. Bob Sutor, welcome to the show.

Thank you for having me.

It’s great to have you here. We’ve had folks on from the companies that eventually merged into Infleqtion, so it’s good to have you on, representing the full brand. Tell us about the company and why its slogan is “The World’s Quantum Information Company.”

Let me say, first of all, we’re good at slogans. A previous one was “Making Quantum Matter.”

That’s funny.

On one hand, we do take atoms and we chill them down close to absolute zero, and that’s quantum matter, and there are fascinating things you can do with it. But it’s also a practical sense of, “Let’s make quantum practical. Let’s make it actually useful for something.”

The company was founded in 2007. Professor Dana Anderson at the University of Colorado Boulder was one of the key founders. It’s not a startup. It has been a small company — less than 100 people — for most of its life span. But starting about four years ago, they started to think about using the cold- or neutral-atom approach not just for sensors and atomic clocks but also for quantum computing. Hence, enter venture capitalists and investors and things like that, because when you’re working on hardware at that scale, it gets expensive very quickly — as well as building up the staff.

It’s a company that has done very well through the years, starting with this core technology of, what happens if you take certain atoms: cesium, rubidium — those ones you may not have noticed in the middle of the periodic table. They have very special properties, particularly when you hit them with lasers. In fact, our CEO, Scott Faris, is fond of saying, “We shoot lasers at atoms. That’s what we do for a living.”

Someone asked me a question: “How do you find the atom? How do you actually find it to shoot it?” That’s another thing. This technology is surprisingly versatile. Before I was at Infleqtion, I was at IBM for many years, in IBM Quantum, and they have a great approach with superconducting. It’s been a program going on for decades.

But I was fascinated by all the different things you could do with this cold-atom approach. If you think of it as quantum computing — organic quantum computing — we are taking things in nature that are normally quantum particles, that normally exhibit quantum properties, and using them to our advantage. That is, we’re not manufacturing things that behave like nature. We’re actually using nature. This means trapping the atoms using lasers, steering them along using more lasers, putting them in the right position using more lasers, executing operations on them, in the case of computing, and exploiting these properties of superposition and entanglement and interference.

It’s an established company that is now looking across the spectrum fundamentally, now looking to productise quantum atomic clocks, looking to move those through the years, first for government and eventually for commercial use, and then things like quantum radio-frequency receivers. Who would have thought you can make an antenna out of very cold atoms? Lots of things to talk about.

We’re going to click into all those today. Let’s start with the antenna, because that’s probably one I would bet no one’s heard of.

Let’s first think about the spectrum: We toss around numbers like 2.7 when we talk about cell phones, certain frequencies on which signals are transmitted. The range of frequencies is very large. I grew up with FM radio — 98.7, things like that. That’s not just a number — it’s a frequency. And when I think back about listening to an FM radio, if I was driving, I’m hearing the music. And as I drove further from that source — maybe I was driving toward another city — lo and behold, there was another channel that had a frequency very close to it, and I started getting interference with it. I could hear both of them a little bit, and then some static and things like this.

Traditional antennas for radio frequencies — and this is the full gamut, not just what we listen to but also light and microwave, the whole range of things here — when the government gives out this spectrum — as I pointed out, 98.7 — they give you this, but they also give you a little bit on each side to try to avoid this collision problem here. And there’s only a limited amount of this spectrum that is useful practically today.

What if we could make antennas that were much more sensitive? In this case, my 98.7 nailed that one frequency. If I wanted to use 98.72, I could do that now with these quantum radio-frequency receivers or antennas, and I could also push out the useful spectrum.

One thing to remember about quantum sensing is that it provides very high resolution. A lot of people know what MRIs are: If you’ve ever had a knee problem or a shoulder problem, you’ve had an MRI so they could look at what was going on. That is a quantum sensing application. It has been available since the 1970s. This brand-new quantum thing is maybe half a decade old. And people started using MRIs because they were safer and they had higher resolution in X rays. In the same way, radio-frequency antennas — the quantum flavors — have much higher resolution. They can use much less power and be much more versatile.

The military likes this. I am told if you looked up the side of a battlecruiser, you would see all these antennas. More actively, in our day-to-day lives, you see cell phone towers. You look up at the top, and there are these big boxes and horns and things like that. Many of those are RF receivers. We can replace those, we believe, in time with things that are about the size of a large smartphone, and perhaps four or five times thicker. And that’s tunable. We can tune it to any frequency we want.

It sounds like there are a lot of areas of sensing that aren’t getting love in terms of the industry, because this is very commercial, as you said— MRI since the ’70s. Can you give our listeners a simple little 101 on what quantum sensing is so they can wrap their head around it on a bigger scale? For some of them, they only think of quantum computing.

Let’s think about here’s my recent favorite example, which is a traditional gyroscope. Today, commercial airliners use what are called ring gyroscopes with lasers. It’s an interesting idea: Imagine I’m holding up my hands to try to make a circle with my fingers here. Imagine rotating this circle clockwise to simulate the idea that the plane is rotating. How the heck would I measure that thing? Today, we take a laser and, from the bottom, we split the beam. We have now two laser beams, and we shoot them around each side of the ring, and they come out again near the bottom. And we did it in a circle, and if nothing was rotating, those beams would merge, basically being identical. They were identical to begin with. We just split one beam into two pieces, but they were identical.

However, if there was any rotation whatsoever in that, one of the beams would have traveled a slightly longer distance and the other beam a slightly shorter distance. When they popped out at the bottom, the properties of these beams would be different. In particular, if we think of these as waves — if you’re more math-inclined, think of it as a sine wave, up and down, snaking up and down, or of dropping a petal in a pond or something like that, imagine dropping two petals and having the waves combine with each other. This is interference.

The same thing happens in the case of rotation with our laser beams. There’s a little bit of interference. We can measure that, and that can tell us how much rotation — not bad. With quantum, we can be even more sensitive because we are replacing this ring with a ring of cold atoms, and we are taking advantage of this notion of superposition.

People sometimes think about superposition in quantum computing. They might say 0 and 1 at the same time. Or Schrödinger’s cat. Is it alive? Is it dead? Is it both? Well, this gives us two things. Whereas originally, we had two different laser beams, we had two different states of quantum matter here. And once again, if there’s any rotation, we can detect that interference at a much finer resolution than we could have even with the fancy laser setup. It’s these fundamental properties that people may have heard about, but casually, like superposition in quantum computing and interference, which can be used for, as I just described, gyroscope rotation. They can measure the change in your speed. They can measure gravity, any of these inertial changes to movement in any direction, with very fine resolution. And that’s why people are so excited about them.

The range of using these types of sensors in industry is huge. I could see it being used in astronomy, for example, like radio telescopes. You’d be able to get even greater resolution that way without having a giant device.

That’s true. We could do that. But let’s even bring it closer to home. Let’s put it in your car. Because all of these things, with a highly accurate clock — an atomic clock — because, remember I mentioned speed, distance, divided by time. Rotation— how much have you turned in a unit of time? At the heart of all these things— which we call PNT: positioning, navigation and timing — is a highly sensitive atomic clock. And if I know where I’m starting, and I have a very accurate clock that stays accurate for a long time, and I can detect my movement in three dimensions, if I know where I started, I know where I end up after a certain amount of time, which means I don’t need GPS.

We had on Boeing talking a little bit about what they’re trying to do in this space. It’s interesting to hear your take on this.

For a long time, I was skeptical about talking about GPS replacements because I was wary to say, “This is something that’ll just never happen.” We’re going to scare people if GPS goes away. And then I started reading more. There was an article last month out of Israel that said that Tel Aviv had a six-month high of GPS spoofing and denial, and a commercial airline pilot said that he was going in for a landing at the Tel Aviv airport, and it said he was actually in the mountains around Tel Aviv. Suddenly, all these sensors started going off, and lots of interesting things happen over there. Evidently, there’s a Russian base in Syria and there are drones, so they’re trying to block GPS.

Well, the Israelis on the other side, according to this article, also have their base, and they are blocking. All the way out to Cyprus, you’ve got this mess of what’s happening with GPS. And suddenly, it’s not just the bad guys, the other, that’s doing this to you. We’re all doing this, and it’s messing us up. And we’d love to stop.

I gave a talk in Colorado last month, and I found this example that GPS had been messed up within 50 miles of the Denver airport for several hours one day. This is not FUD. This is something that’s happening, and this is something that’s well within our capabilities of ultimately building and replacing GPS with these quantum sensors.

Do you think replacing, or working in tandem?

For a while, it will be in tandem. For example, let’s imagine a submarine under the water, not getting that much value from GPS. They might have to surface every once in a while to get a reading of their specific location. With these more sensitive and more stable types of sensors and clocks, it means they can stay under the water much longer. You might still want some way of asserting absolute position that might not be GPS. There are, in fact, some land-based ways of doing this. It’s an augmentation — or even if it’s a double-check, am I where that tells me I am? They’ll probably exist in that way for a while.

I’m a fan of more sensors is better — more types of sensing. When Tesla got rid of everything except cameras, I couldn’t wrap my head around that. Why would you give up lidar? Why would you give up all these other ways of seeing the world and having better object detection?

Avoiding single points of failure.

Exactly. In what other areas can sensing be used? Is there anything involved in climate research right now with the way things are?

Rather than just think of climate, let’s just think about what we call metrology, which is measuring things on Earth. There are some experimental applications that can determine chemical compositions of certain things— the air in certain spaces — and quantum sensors might be able to do that.

But let me get back to gravity. I have a renewed appreciation for gravity, and when I was in the UK a couple of weeks ago, I was, like, “ Isaac Newton would love this story.” A lot of people tend to think about, they’re walking around at sea level and the gravity is perfectly constant, and maybe they know a few numbers, like 32s or nines or things like this. But gravity actually varies very significantly as we move around.

Let’s say you were in an urban center and you were walking down the street, and you didn’t happen to know this, but there was an underground parking garage. If you had a sensitive quantum gravimeter, you could tell by the change of gravity what that boundary was, because the gravity would be a little bit less while you were over the parking garage, and then it would increase. Now, also, gravity going up and down — of course, that’s one thing: measuring heights and different things like this. It does have military uses. They’re very interested in hidden bunkers and that type of things. But if a building collapses, is there a void where survivors may be trapped, may be saved? Volcanoes — we use gravimeters today. They put gravimeters around volcanoes. As the magma chambers start to fill up with magma, indicating an eruption is likely, the gravity increases.

If we can put more of those and cheaper of those in more places, we might be able to get more advanced notice of certain natural disasters — not just volcanoes, but it could be earthquakes, it could be tidal waves, it could be things like this. Let’s think about climate in the way of changes to the Earth environment. Rather than climate, think of changes to the Earth environment as measured with quantum sensors to give us early notice in order to do something better and we hope, life-saving with it.

In this case, more of these gravity meters, would they be able to increase the resolution?

That’s right. On one hand, they would increase the resolution. Right. Now, gravimeters are about the size of the thing that you would put in the back of a pickup truck. And here I want you to imagine maybe somebody’s involved with mining in Australia or Brazil or someplace like this. They want something portable. Eventually, we would want these to be much smaller.

This does lead to something as we try to imagine, what will stop this possibly from happening? It’s the photonics. We talked about, at Infleqtion, cold quantum — we shot lasers at atoms. Photonics are a key part of all of this. And thinking of quantum computing, it’s not just cold or neutral atoms. It’s things like ion traps. It’s things like nitrogen vacancy. All the nonsemiconductor approaches for quantum computing use lasers, use photonics. What we need in the long run is to drive down the size and the cost of these to ultimately get photonic integrated circuits.

And that will — we hope in about 10 years, assuming everything goes well in that parallel industry — be able to give us clocks that are perhaps size of a couple of coins stacked, smaller radio-frequency antennas that we talked about, a little bit bigger than a cell phone, and gravimeters as well. We’ll go from what looks big now down to a rack size, down to something smaller, and if everything goes well and everything falls into place and we get the right government funding and impetus to support this, down to something much smaller that will fit in your hand.

When you’re thinking of quantum sensing, typically I hear it in conjunction with networking: You want these sensors to be able to often communicate with each other while maintaining quantum information. What’s Infleqtion seeing in quantum communication these days?

If we start with quantum communications, a lot of the discussion immediately goes to secure communications. People think about quantum key distribution — securely sending something over a line, and it’s typically fiber optic. Lasers come back into play yet again. But if we think about a sensor, what is it doing? It’s absorbing information from the environment. As you mentioned, it could be radio waves, radio frequencies. It could be that for communication or anything else. We could be measuring gravity, we could be measuring speed — any of these types of things. The point is that quantum sensors give you a very nice way of taking data in the environment and quantum encoding it.

We think of qubits in quantum computing in the same way. If you think of those atoms in the sensors, we can think of those as qubits —this fast and natural way of taking this information and encoding it in qubits with all the advantages we have. Every time you add a qubit, you can double the amount of information. That sounds interesting. And today, sensors may convert to other forms. They may convert to digital forms — zeros and ones — maybe an analog form.

But what if we wanted to keep that information in quantum form? What if we wanted to move that information so we could compute with it in a quantum computer? It turns out, as people think about quantum computing, they say, “I have this database of information. I’d like to put this in a quantum computer and think about all the things we can do with it.” That is very expensive. In fact, it can be exponential to take regular classical data and just stick it in a quantum computer. And, by the way, with today’s quantum computers, you’re going to run out of time. You’re going to load your data and have no more time left in the qubits to do anything useful whatsoever.

You get it almost for free from sensors. We need to network the sensors to quantum computers and eventually sensors to quantum storage facilities, quantum memory. This has opened up a whole new type of networking beyond what we’ve thought about before: What does it mean to transport two entangled qubits or two entangled quantum particles across a network? How does that work? They’re operating as a single object, if you will. How do you do that? How do you actually take whatever’s going on inside the sensor and put it in an optical form for photons and then ship it across? What happens if it starts picking up noise? I can’t send this a long distance. I can’t send it a thousand miles. I have to have repeaters, but I need quantum repeaters, not classical repeaters.

Yeah, they’ve been a sticking point — quantum repeaters, the no-cloning principle. It becomes a problem.

That’s right. When I first heard about the no-cloning principle, which says very simply, if you have quantum data, you cannot make a copy of it, I was sitting right here, and I said, “You’ve got to be kidding. Where do we go from here?” But you’re imagining these classical approaches to problems like networking, and then you’ve got to turn your head 90 degrees and think about it in a whole other way. Maybe repeaters are, for example, small quantum computers, because they have to do operations.

How small? If they’re small quantum computers — and all this big focus has been on quantum computers in the data centers, quantum supercomputers — what about quantum computers at the edge? That’s where a repeater would live, Or in a data center, but in the networking part of the infrastructure — it’s not taking up all this room on the floor.

A lot of what we do with Infleqtion, thinking about taglines and slogans, we believe in looking at the edge — the applications. Sensors live at the edge. What will computing mean at the edge? What must be the capabilities of them? How big is big enough for quantum computing for these types of applications?

We’ve learned from computing over and over, yes, we start with great big computers — mainframes. Now we have phones. My phone would have been a supercomputer 30 years ago. We know how this is going to play out. We’ve seen this movie multiple times. Rather than worry so much on yet one more flavor of a quantum computer in the data center, let’s look beyond that. Let’s bring some of these other technologies to market sooner, like sensors, like atomic clocks, like RF receivers. And that’s why we think there’s a good chance we’ll see commercial value from these, and even more commercial value, before we see it coming for quantum computers.

What roadmap do you have? It’s been a while since we’ve talked to the cold-quantum side of it. We had Hilbert. That was a hundred qubits. Is there anything you could share about the next generations coming?

Hilbert — that is the name of our quantum computing effort — we consider an R&D project at this point. We put it on the cloud for a few weeks last year, and then we took it down. We probably could have been a little bit more explicit about it being a prototype because when we looked at it — and, particularly, we looked at the photonics — we realised we could do better. Ultimately, we need it to run circuits faster. We need to run them with greater fidelity —fewer errors. In some sense, you can imagine taking the machine, taking it apart, all the pieces are on the ground, replacing certain parts of it and then bringing it back up to increase what’s called the repetition rate, but also the fidelity and especially with the two qubit operations that we do.

For those of you who know quantum computers, people talk about CNOT or CX two-qubit operations. Ours uses CZ operations and controlled-Z gates. We have decided that we are still working on this 100-qubit generation, but we’re working on the control aspects. We believe that likely, we’ll go through two or three generations. The current generation, roughly, will peak around 100. The second generation will be about 1,000. We know that we can do some of this because we’ve already built a proto–qubit array where we have had 35 by 35 atoms arranged like a checkerboard, and that’s what they look like in these applications. We’ve successfully been able to lay that out.

And that checkerboard, that array of over 1,000 atoms, is just about the width of a human hair, and it’s in a glass cell, and it’s programmed using lasers. We will then have some decisions to make about what we want to do. Given the progression here, the reasonable thing is to look at, can we put 10,000 qubits on this? That would be great — and I can see our doing that.

A lot of these numbers are significant. Let me call such an array a quantum core. If we look at IBM and they have a chip with 100-something or 400 qubits on a chip, that’s a quantum core. It’s a fixed unit — it’s the entire quantum processing unit — but it’s a fixed thing with a fixed number of qubits in it. Ion traps, right now, they have a few dozen. We think we can go to 1,000. If things work out and we want to do it, maybe 10,000.

This becomes very important for error correction because right now, despite what some people say the best estimates are, we’ll need somewhere between maybe 700 and 1,300 physical qubits for one error-corrected qubit, one logical qubit. You’d love to fit all those in one core. You’d like to have all those operations happening in one core. If you have significantly less than 1,000, you’re going to have trouble. You’re going to have to start networking the cores together. And how easy is that to do, and what methods might you apply? It’s for this reason that we could look at improving the fidelities, how we will scale, looking more practically at what the uses of quantum computers will be at the edge versus just in a data center. And we’ll also start to think about these notions of networking the cores together to build bigger quantum computers. That’s why we pulled it back into R&D.

Now, in terms of the other products — atomic clocks, atomic clocks. Atomic clocks. Those will show up everywhere. We mentioned a few applications. Timing is critical just for traditional networks, high-speed networks. There are, in some sense, pauses in networks. Things are sent around in packets. Transactions have to be timed. If I’m doing high-speed trading back and forth, timing is critical.

When I was growing up, “Where does energy come from when you plug something?” It came from that nuclear power plant or that coal power plant, or maybe, if you’re near Canada, a hydro plant. But it came from these great big, colossal energy generating plants and flowed through the network to me. Now we have windmills, and now we have solar panels. Some are commercial, some are on people’s roofs. We have geothermal. We have things coming from many different sources entering the network and then going back out and sharing. This network is very much more complicated and bidirectional in many cases. How do you optimise this? The timing is critical for the control. Once again, atomic clocks, and many of them throughout. This is why we believe that atomic clocks will, over time, become pervasive across what we do.

When you think of atomic clocks, you think of the big cesium one that is used for its accuracy. And you mentioned cesium earlier, so it makes you wonder: Are we going right back to cesium again?

Cesium and rubidium are very good choices. In general, people throw out a few more types of atoms for these general quantum applications like strontium and so forth. They all live in the same neighborhood of the periodic table. Some of them are a little bit better than others based on the types of lasers you use, things like, how much does it cost to get a laser at that frequency? But down deep, they’re going to be these little glass cells filled with some cesium or rubidium atoms with little photonic circuits optically driving, what they do. That’s what life will be like in 10, 15 years.

We’re going to be replacing the big atomic clock with these tiny little ones soon?

Well, not in 2024. Let me actually do a plug. I’m sitting here in upstate New York. In moving to, first, ColdQuanta, which then renamed itself Infleqtion, I got to go to Colorado, where the company was founded — in particular, Boulder, Colorado. I had no idea of all the quantum things going on in Boulder, Colorado. The cesium clock you mentioned — it is in fact the most sensitive, stable atomic clock in the world — is in Boulder, Colorado. The number of research physicists — right there in the middle of the country. There is such a wealth of physics scientists and engineers that are based in Colorado, doing a lot of this work. To be in this community with all these people doing the types of quantum things that, frankly, I had no experience with has been a real joy, and intellectually interesting.

It’s almost like a mini quantum Silicon Valley that people haven’t paid enough attention to in some ways.

Is it like the Quantum Range, or the Quantum Rockies. I call the corresponding New York version, by the way, the Quantum Thruway, because upstate New York is yet one more place. Rochester, New York is one of the three major photonic centers in the United States. You’ve got the Air Force research laboratory east of here in Rome. The quantum world is growing up outside Silicon Valley in some very surprising places, and it’s an interesting side story when people look at this and ask why, and what is the history — how it’s all coming together.

If you had to, in closing, make a prediction, what would be the first killer application for something like an edge device, be it a sensor or something like that? What do you think is going to just take off overnight once it hits?

It’s going to be, initially, these rack-size atomic clocks and then moving a little bit smaller. And we include that in the general sensor category — things to do with cold atoms in different ways. Along with that, we’ve got a lot of interest in the RF receivers, the antennas.

Second, I’m thinking a good bet is with gravity. Again, strange as it may seem, a lot of what happened with quantum computing — I was involved with a lot of the early making it public and educating people when I was with IBM, along with many other people. But it was one of these things — “Quantum — that’s so cool! Tell me about it. Computing. I know what computing is!” Gravity is another one of the things that people, in a real sense, fundamentally get. And the applications are going to be very rich — they’re going to be very tangible in many ways in our life. And the gravity sensors will help explain the value of the other ones. Commercially, as I described it, atomic clocks plus quantum RF receivers, gravity as the big explainer topic that brings sensors home to people for the value and just to know how they work.

And just think if there’s some disaster movie in the future, you could imagine these gravity sensors being involved.

I enjoyed this. I thought this was great. We don’t talk about sensors enough, and you did an amazing job of making it clear what they are.

It’s a fun topic, all these quantum things, the more you learn about it. Gyroscopes — I knew nothing about gyroscopes. Quantum is something where you learn something new every day, and in terms of computing, it’s going to be the killer tech for this century.

We’ll be partnering with Infleqtion as part of Chicago Tech Week on July 13. Peter Knowle, who was on the show before, he’ll be doing a fraud-detection demo with us. It’ll be good to see some Infleqtion folks again soon in person.

That’s right. More from a software angle. We didn’t talk about software.

Yes. Thank you for coming on.

Now it’s time for Coherence, the quantum executive summary, where I take a moment to highlight some of the business impacts we discussed today in case things got too nerdy at times. Let’s recap. Since 2007, Infleqtion has been focused on using cold, or neutral, atoms for sensors, atomic clocks and quantum computers. They basically shoot lasers at atoms, to quote their CEO. But it’s not that simple. Lasers trap, steer, position and execute operations on atoms. That leads to an array of usable technologies. Infleqtion is applying the technology to antennas that are more sensitive.

On that note of increased accuracy, we get to other types of quantum sensors. Laser-controlled gyroscopes can use the technology for more accurate positioning. Highly sensitive atomic clocks enable this, allowing for non-GPS navigation that keeps track of movement. Gravimeters are an even more futuristic-sounding application of quantum sensing: Imagine detecting changes in gravity caused by something buried deep in the Earth, for instance.

The cold- or neutral-atom approach does not require large refrigerators and is expected to be used in the next-generation version of Hilbert, the company’s quantum computer. They’re targeting 1,000 qubits in 2024, all at room temperature.

That does it for this episode. Thanks to Bob Suter for joining to discuss Infleqtion’s technologies, and thank you for listening. If you enjoyed the show, please subscribe to Protiviti’s The Post-Quantum World, and leave a review to help others find us. Be sure to follow me on all socials @KonstantHacker. You’ll find links there to what we’re doing in Quantum Computing Services at Protiviti. You can also DM me questions or suggestions for what you’d like to hear on the show. For more information on our quantum services, check out Protiviti.com, or follow ProtivitiTech on Twitter and LinkedIn. Until next time, be kind, and stay quantum-curious.