Rene: Hi! Welcome to Season 2 of QuBites, your bite size pieces of quantum computing. My name is Rene from Valorem Reply and today we're going to talk about [the] quantum computing hardware landscape and I'm very honored to have a special expert guest today my fellow Microsoft Regional Director and MVP Ciprian Jichici. Hi Ciprian, welcome to the show! I know you as an RD and also that you have your own quantum computing podcast but can you tell everyone a little bit about it and yourself and your background as it relates to quantum computing?

Ciprian: Hi Rene, very very happy to be on your on your podcast! As you mentioned, I'm a Microsoft Regional Director [and] I'm a [Microsoft] Most Valuable Professional (MVP) on artificial intelligence (AI) and quantum computing. [As] you mentioned, I have my own podcast,, is a podcast that I've launched this this year. My interest in quantum computing goes way back in college when I was a big fan of quantum physics. I would call myself a failed physicist actually, I ended up in computer science but that was kind of my first scientific love, and now I get to practice it with quantum computing.

Rene: Nice! That's awesome! And we're not just both [Microsoft] Regional Directors and MVPs, we also were both born behind the Iron Curtain and are now [we are both] working on this modern technology! And that's just awesome! But let's dive into today's topics about the quantum computing hardware landscape. What kind of different quantum computers are out there, and you know which is, in your opinion, the most promising approach that is being a tangled?

Ciprian: Well, I think at the moment there are two major categories of quantum computers when we speak about the hardware itself. We have the circuit-based quantum computers and then we have the hardware that is based on quantum annealing. And the big difference between the two of them is that the circuit-based computers are the ones that aim to implement what we call universal quantum computing. Meaning that you could run virtually any program on them. While the annealing ones are limited to a specific class of problems that they can solve, namely optimization problems. Obviously from my point of view the most promising one is the first, the circuit-based quantum computers because those are the ones that promise the full power of quantum computing.

Rene: Totally get it there, it makes more sense generally, right? And with quantum annealing and the optimization you mentioned you can implement this quantum tunneling approach, right? Where you can just basically skip an energy level. That's the current approach that we see from some vendors because it's easier to implement than the circuit-based ones, right? And so, speaking of the vendors and well the players in the field, if you will [share], what are some of the major research institutes and also technology players that are developing their own quantum computers?

Ciprian: Yeah, before that I would like to add one more thing because it's the source of a lot of questions that I get. It's in the number of qubits that are available, right? With quantum annealing computers, you typically see larger number of qubits. But those are not the qubits that are based on the circuit approach, which are basically the ones that we're looking for to get into what we call quantum supremacy. The most important player in terms of quantum annealing computers is D-Wave and it's the one that actually is driving the field. On the circuit-based part, we have a larger field of players ranging from startups like Rigetti or big players like IBM, Google and also Microsoft, which has not yet a working physical quantum computer but it's developing it on a different approach that is based on topological quantum computing. There are also several major universities of the world that are playing in this particular field. So it's a field with some very large players but also with some very important startups like Rigetti or D-Wave or the others.

Rene: And IonQ and a few more that are working on it. Speaking of the topological qubit approach that Microsoft is approaching, I keep on hearing that is probably, if they can make that happen, that's probably the biggest kind of milestone. What is your thinking about that?

Ciprian: The big problem with circuit-based quantum computers is what we call the decoherence problem. And without getting into the math, it's literally the problem of isolating the qubits from the outside world. That's one of the largest problems, the biggest problems these folks need to solve and that's the reason why we don't have too many working circuit-based qubits at the moment. And this is where Microsoft tries to play differently in a sense that the topological approach has the promise of making it simpler to isolate qubits. Which in turn means you need less physical qubits to build the logical ones, less error control, and obviously you get a more stable system with a larger number of qubits. That's the promise, right? It's a long way to go though.

Rene: Yeah, totally. And you already mentioned quantum supremacy and that some players in the field already announced that they reached quantum supremacy. Maybe you can just tell what is actually quantum supremacy? And also, what do you think about this claim that was actually made? Then some other players/companies said, well that's actually not a real claim. So, what do you think about that?

Ciprian: Well, quantum supremacy actually refers to the fact that a quantum computer can execute an algorithm in a short amount of time compared to the time a classical computer would meet it. And usually, it's several orders of magnitude. Like a quantum computer will do let's say a factorization in the order of hundreds of seconds while a classical computer, no matter how powerful, would need hundreds of years to do it. [Quantum Supremacy] actually has two aspects, one is the actual building of the hardware and the other one is the algorithms that are capable of using it. Unfortunately, from my point of view, this went into the realm of marketing hype. The reality is that today we simply do not have a large enough number of stable qubits. That's the big difference, that's where it's kind of you know the fine print. You always need to think about it, it's not about the number of qubits you can build, it's the number of qubits that can simultaneously be in a coherent state so that you can run computing. And at least based on public evidence, we're not there yet. So I have serious doubts that any company today can claim actually reaching quantum supremacy.

Rene: Alright, that’s good to know, right? It's like saying hey we have 2,000 qubits and then in the fine print it says, hey but they collapse in a few nanoseconds.

Ciprian: Exactly. And we can keep like 10 at a time in a coherent state so that we can run actual computations. And that was a great thing that you mentioned about nanoseconds. When we're saying keeps stable, you need to think at a completely different level. Like, for example, keeping [qubits] stable for 2 milliseconds would be an amazing feat of engineering and would actually allow the run of a lot of powerful algorithms. So that the time here, the time spans, are totally different from the ones that we are used to working with in classical computing.

Rene: Totally, makes sense. Well, we're already at the end of our short show today and thank you so much Ciprian for joining us and sharing all your insights about the quantum computing hardware landscape. It is very much appreciated, thank you so much!

Ciprian: Thank you very much Rene for the invitation. It has been a joy to discuss with you this topic!

Rene: Thank you!

And folks, make sure to also subscribe to his podcast called Entangled Things. It's awesome and it's a little bit longer than our show here, so you get more details if you are interested in that. So check it out as well!

And thanks everyone for joining us for another episode of QuBites, you're bite sized pieces of quantum computing. Watch our blog, follow our social media channels, to hear all about the next episodes that we will be releasing. Take care, be safe and see you soon! Bye, bye.