Quantum computing remains a science-fiction catchphrase for many. But according to IBM CEO Arvind Krishna, his company’s clients could be using the technology, and reaping huge benefits, as soon as 2023.

“The impact [of quantum computing] on our clients…is going to be in the hundreds of billions of dollars,” Krishna said at today’s Fortune Brainstorm Tech virtual conference.

Those benefits will be particularly pronounced in medicine. “If you want to understand penicillin or caffeine, you can’t do that on a conventional supercomputer, no matter how big you make it,” Krishna explained. The subatomic randomness that gives those precious substances their powerful effects are difficult to model with conventional computers, which consist of simple on-off switches known as bits.

By contrast, a quantum computer can mirror randomness. That’s useful not just for medicine, but materials science, weather forecasting, financial modeling, and other problems that involve huge amounts of data and chaotic interactions.

Quantum computing may eventually help IBM solve a more mundane problem: how to keep revenues growing.

Krishna, who succeeded Ginni Rometty as IBM’s CEO in February of 2020, has long focused on cloud computing services, culminating in the acquisition of Red Hat, which he spearheaded before being named CEO. In October, IBM announced plans to spin out slower-growing parts of its business and to focus on cloud and artificial intelligence. Quantum computing, though less strategically central, would also remain under the IBM umbrella.

Speaking to Fortune’s Aaron Pressman, Krishna focused on IBM’s “hybrid cloud” strategy, which the company says represents a $1 trillion market. IBM’s main goal is not to build their own cloud services, but to help big business manage multiple clouds. That’s an appealing proposition not just because different cloud providers offer different strengths, but because dependence on any one vendor is risky.

In October, IBM reported that its cloud services revenue for the prior 12 months had grown by 25% from the previous 12 months. Krishna said those results are being obscured by slower-growing IBM units, such as IT infrastructure services, and that the planned spinoff will clarify IBM’s core strength. The COVID-19 pandemic has dramatically accelerated growth in cloud computing.

The pandemic has also changed how offices work, and Krishna provided some insight into IBM’s mindset. Only 10% to 15% of IBM employees, he noted, are working in offices, with the rest still remote. Krishna thinks that shift is basically here to stay.

“The office becomes a place to meet,” said Krishna, “Not a cubicle where you do routine work.”