IBM on How Qubits Increase Quantum Compute Incrementally

Qubits are often said to be the quantum computing equivalent of bits in classical computing, so the hundreds of qubits offered by even the latest quantum computing technology sound unimpressive.

However, the quantum physics properties of qubits mean processing power increases exponentially as you add more qubits, as IBM distinguished engineer and quantum ambassador Richard Hopkins explained at a recent technology demonstration event at the company’s London headquarters.

Incremental processing power

IBM’s quantum computing technology uses superconducting cooled qubits.

The company’s current state-of-the-art quantum processor is the Eagle, which boasts 127 qubits and was announced in late 2021. Later this year, the company plans to release the 433 qubit Osprey, followed by the 1,200 qubit Condor in 2023.

But the quantum phenomenon of entanglement (when two paired qubits share the same state and changing one instantaneously changes the other) means the processor power will go up by a factor far greater than the number of qubits added.

“Every time you add a new qubit to the quantum computer, and you entangle it into its quantum state and do calculations on it, it doubles the power of the computer,” said Hopkins. “The power of this Eagle machine is two to the power of 127, which is a very big number indeed. It's about half the number of atoms in the Earth.”

By the time Osprey and Condor are running and coherent, they expect to access more states in the quantum computer than there are atoms in the universe.

This makes quantum computing uniquely powerful because the types of problems future quantum computers will be asked to solve, such as the orbit of a newly discovered planet or the effect of adding another atom to a molecule, would double the processing power, memory and power consumption for a classical computer.

“In a quantum computer, you add one more qubit, entangle it and you've essentially doubled its capability to do these things,” said Hopkins. “There's a certain type of problem that quantum computers can do that traditional computers can't.

“We've got clients working with us to make it a commercial reality for things like fraud detection in banks. We've already got a quantum computer working with our IBM safer payments capability, which we use to secure lots and lots of banks around the world, including the whole of France.”

Hybrid capability

Hopkins said hybrid algorithms, which run on classical computers enhanced by quantum processors, already provide greater accuracy than classical computers alone and use cases are likely to grow over the next few years.

“These may be classification problems, such as is this transaction fraudulent or not? Then perhaps move on to optimization problems, how do I best do this? What's the best time to sell this particular portfolio or how do I reorientate this portfolio to allow for minimal risk?”

This could lead to more complex problems, such as determining whether a bank is liquid, which now is very complicated to work out and takes a lot of processing power.

“Quantum has the capability of starting to address those kinds of horrendous problems and at a level of accuracy and capability in the future that no supercomputer would ever be able to do,” Hopkins said.

Quantum ecosystem

While IBM has become an industry benchmark for quantum computing, it has not done so alone, and the ecosystem it has built around its IBM Quantum Network has ensured its technological breakthroughs have solid scientific and commercial backing.

“We work with 150 or so partners within our ecosystem for different industries, universities, organizations and banks, and we've been doing joint research as a group for the last few years,” said Hopkins.

“We were the first to put quantum computers on the web in 2016. You can access the 20 or 25 systems in our data center in Poughkeepsie now via the cloud. Few people will have dedicated machines so will access the kinds of algorithms I've been talking about using the serverless paradigm.

“It’s going to be an interesting change of perspective as this transitions from a research technology to an early adopters technology. For example, HSBC has joined our accelerator program in the U.K., and they are looking at a three-year horizon to build the skills they need and their early use cases. I have no reason to believe they won't be able to start generating business advantage on that timeframe.”

Obstacles to progress

While quantum computing technology has made great strides over the last year, coherence length (how long qubits can retain their quantum properties before errors occur) is still a challenge for researchers.

“Coherence is our biggestproblem, but we've made amazing strides on that,” said Hopkins. “We've gone from a few hundred microseconds to a millisecond, which is extraordinary, and I'm sure we can find ways to go beyond that, especially bringing in error mitigation and three-dimensional error correction, which are part of our quantum roadmap.”

Despite that, Hopkins believes the future is bright for superconducting qubits.

“That's not to say that other qubit technologies won't get there and won't do useful things. Some of them have different strengths and weaknesses,” he said.

“It's going to be a fascinating time. I think IBM has got the right combination of technology, software and partners, and a focus on doing something useful as opposed to doing pure science. We did that back in the 1990s.”