DARPA’s explorations in quantum computing search for the art of the possible in the realm of the improbable

Quantum computers could be a game changer – if they work. (Getty Images)

To discuss the state of quantum computing and its military applications, we spoke with Joe Altepeter, a program manager in DARPA’s Defense Sciences Office (DSO). Altepeter manages two of DARPA’s three main quantum programs – including the (US2QC) program, which deals with the discovery of new, novel and overlooked avenues in quantum exploration.

Breaking Defense: Quantum computers are talked about as something that can be both offensive in the sense that it has the ability to break all known encryption, and defensive in preventing adversaries from breaking US encryption. What is the priority for the US government? Or is it both?

Joe Altepeter is program manager of DARPA’s quantum program called Underexplored Systems for Utility-Scale Quantum Computing.

Altepeter: I’m going to choose secret option number three. The interest in quantum computing began in 1995 when Peter Shor discovered an algorithm to efficiently factorize large numbers. I’m not an encryption expert, but I don’t think it breaks all types of encryption, although it definitely breaks some like RSA. This is why NIST and such agencies are developing alternative means of encryption that are resistant to the kinds of quantum attacks you’re talking about.

At DARPA, our mandate is to eliminate strategic surprise. While people have been thinking about quantum computing and factorization for decades now, we’re interested in the next application that might surprise us all and lead to a computing revolution. We are interested [knowing if there] are there other surprising uses of quantum computers.

If we can build a quantum computer, will it really change how we think about computing and revolutionize computing disciplines? Or won’t it really do something that a classic supercomputer couldn’t? The result of that is, let’s assume it’s going to be revolutionary. These computers are really hard to build. Is there a surprising path to building one that the conventional quantum computing community might have overlooked that DARPA needs to figure out [about] will this path work?

Of the 10 smartest physicists I know, about half are convinced that quantum computing will totally revolutionize computing in the 21st century and be a revolutionary way to solve problems from materials science, to chemistry, to mathematics, to optimization. The other half are convinced that it will never do anything that a regular or classic computer cannot do.

When I think about strategic surprise, it’s hard for me to think of a discipline that has more potential for surprise than one where we think it’s somewhere between totally revolutionary and totally useless. It’s somewhere in that zone. DARPA wants to try to bring some clarity to that question.

DARPA says many physicists think quantum computing is revolutionary. Others think it won’t be much better than today’s supercomputers. Shown is a Cray supercomputer at NASA’s Lewis Research Center in 2009. (NASA.)

Breaking Defense: What is the status of quantum in the DoD now? Is it still only the domain of DARPA and the other research agencies?

Altepeter: As far as I know, the DoD is not currently using quantum computers for any real-world problems. However, quantum computers, and especially those being developed in commercial industry, have done amazing, almost miraculous things. Quantum computers have now been shown to be able to perform calculations that are completely impossible for any classical computer anywhere on Earth to do.

You and your readers may be thinking, it certainly sounds like it’s useful that they can do something that is completely impossible for anything else to do. At this point, quantum computers are used for proof-of-principle problems that show we can do something that nothing else can, but we haven’t taken that next step to bend that computing power to a useful problem that we really need. an answer to

For the DoD, that means having an effect in the field, doing something we care about. There are many tempting paths. If we keep getting better quantum computers and better understand how to bend them to the problems we care about, we might be able to solve corrosion resistance and save the Navy billions of dollars in maintaining their ships. Maybe we can come up with better pharmaceuticals and greatly reduce the cost of the drugs we need to care for our people. Maybe we can solve optimization problems and greatly increase the efficiency of everything we do.

That said, from my perspective, we don’t yet have a clear path of how to solve this. The reason DARPA is stepping in is to try to help clarify what the link is and how difficult it’s going to be, if we can at all, link the truly miraculous machines that we have and we’ll have in the next. few years with the problems that the DoD really cares about.

Breaking Defense: When I read the background on DARPA’s three quantum computing programs, I was particularly interested in US2QC because of its mission to accelerate quantum development through unexplored avenues. Describe the program.

Altepeter: There is a lot of hype in this space, which is understandable because people are excited about the potential for this technology. But that makes it hard to tell what’s real and what’s not. Especially when there are many commercial companies pursuing this technology, dozens of them.

Understandably, much of the secret sauce, the things that make their approaches work, are kept as trade secrets. But DARPA is interested in understanding approaches that are different from things we’ve pursued in the past.

We put out a call that said: if you’re a company, university or organization and you think you’ve found the solution to building a large, powerful quantum computer and you think you’re on the way to doing it, want we would like to give you the opportunity to prove it. We will put together a validation team of some of the best experts in and around government and work with you to get you enough funding so you won’t be delayed.

We can provide a lot of value to these organizations by being a neutral third party to ask tough questions. We think they can provide value to DARPA in its primary mission, which is to avoid being surprised if there really is a fantastic route out there that doesn’t look like what we’ve tried before to a working quantum computer. don’t come

Break Defense: In what ways are you trying to speed up quantum development – software, chips, AI?

Altepeter: Until now, for the last 20 years or so, many organizations [though] not all of them are focused on trying to prove that it’s not all just the imagination, that it really is possible to build quantum computers that can do things that are impossible for any other computer to do. We have reached that milestone as a society.

The biggest next step is to start focusing on the end goal. Instead of focusing on whether it is possible to make next year’s computers twice as quantum as this year’s computers, we need to look ahead. Maybe it’s decades away, but what compute capability will be a game changer for the DoD, for the commercial space? What will help us fight climate change? What would make the world a better place?

Focus on that goal and not just saying that it would be really great if we had better batteries or didn’t have to worry about corrosion on naval ships. But instead of saying, “I want this particular computational capability to calculate the structure of this molecule or this material at this scale with these parameters.” If I could do that, I would have a much better chance of inventing something that was going to help the DoD in the field in real life.

If that’s our goal, if we’re trying to get to the moon, we need to stop measuring progress by how high the planes fly. We need to find out what is the R&D path, what are the benchmarks, what is the plan that is really going to get us there?

From my perspective, it’s not a specific chip, it’s not a specific type of interconnect, it’s not getting a CPU speed up to a certain amount. It focuses on our shared goal and then deduces what the most important pieces are that we want to improve DARPA style.

Breaking Defense: Final Thoughts?

Altepeter: DARPA is not convinced that quantum is going to be a revolutionary capability. We are also not a skeptic who thinks that quantum is definitely not going to work. We want to go in with a clear eye and do a rigorous evaluation to see where and how and on what path quantum can make the DoD’s capabilities better, and really make the world a better place. That’s what we’re trying to do, not to prejudge the outcome, but look hard and see what we learn and reduce strategic surprise in this space.