How a quantum computer actually works

IBM’s System One is a quantum computer with its guts exposed, looking like a golden sci-fi chandelier.

It resides in IBM’s quantum computing visitors’ center, which backs onto the functioning facility that offers quantum computing power to a range of businesses and researchers.

IBM distinguished engineer and quantum computing expert Richard Hopkins tells us what goes into IBM’s quantum technology and the company’s ambitions for solving global problems.

We’re looking at IBM’s System One quantum processor. Talk us through what we’re seeing. 

The processor is that tiny chip right down at the bottom. Everything else you can see is there to keep that chip cold, because the magic of the quantum machine, the qubits, will only work if they’re almost absolute zero, colder than outer space.

When this machine is working, there’s a bank of computers sitting behind it, interpreting the signals coming from the machine and sending new signals down.

They’re sent as microwave pulses and all this beautiful engineering is about taking those pulses and making them weaker and weaker by attenuating the signals. Every single layer of this chandelier, as we call it, can interact with the individual qubits on the chip.

To get the results, we take a measurement of the circuit. This then comes all the way back up through the layers and gets amplified in the same steps as it came down.

That allows us to keep this thing incredibly cold and in a coherent state for as long as we can manage.

We’re aiming to get coherency of a millisecond soon, which sounds like a short space of time, but in computing, that’s quite a long space of time.

Everything you see here looks beautiful but there’s also some kind of engineering function. Gold is used to ensure conductivity.

When the machine gets very cold, the wires contract. And if there weren’t those loops there, the whole system would pull itself apart. Although it looks beautiful, everything here is there for a reason.

This is a real machine. We’ve stripped it back so you can see the rather beautiful insides. The real machines are encased in a silver tube and have great science fiction green flashing lights in the back. The sound you can hear is the compressor, which is keeping the helium down at a lower temperature to be able to cool this piece down.

Where physically are IBM’s quantum computers?

We’ve had a total of 54 different quantum computers on the internet in the cloud. Today we’ve got in the 20s, because once we retire them, we replace them in this country. We’ve got 20 physical computers on the cloud in our Poughkeepsie data center. In addition, we’ve already installed machines at the Fraunhofer Institute in Germany, we’ve got one in Japan and we’re about to put one in South Korea. We’ve got our first commercial installation of a quantum computer, happening with Cleveland Clinic over in the States.

If you go on the web today, you can use one of these machines in batch mode. We’re aiming to get into serverless in the next year or so. You’ll be able to interact in real-time with quantum computers on the web and that’s going to be a game-changer.

Next year is the year we’re going to bring out our 1,021 qubit Condor chip. We hope that that will be sufficient to get us to the point where we can demonstrate quantum advantage on a real scientific problem that has real-world implications.

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