The age of quantum software has already started

That means companies racing to keep up with artificial intelligence will need to contend with yet another emerging area of change much more quickly than some quantum timelines suggest.

We already have a few working examples of what quantum software can do, thanks to the ability of early-stage quantum machines and classical computers that simulate what is coming. International Business Machines said it now generates revenue from deploying quantum systems and services to more than 250 customers.

The company said it is using quantum systems with Wells Fargo to potentially improve AI technology, for example, by testing and implementing new machine learning generative models.

IBM’s quantum scientists and the European energy company E.ON have developed an algorithm for managing weather risk using a quantum computer that IBM says could outperform classical methods.

“It’s actually not a matter of waiting for that to be built. In fact, it’s already happening," said Jerry M. Chow, an IBM fellow and director of quantum infrastructure at the company.

Terra Quantum, a “quantum as a service" startup based in St. Gallen, Switzerland, and Munich, Germany, is similarly running quantum-based software on high-performance traditional computers for clients in finance, energy and life sciences, according to founder and Chief Executive Markus Pflitsch.

Select uses of the technology “outperform best-in-class classical solutions," Pflitsch said.

Terra Quantum says it has developed quantum-based algorithms that more efficiently model the value that is placed at risk in various scenarios, which is important to insurance companies and other financial service providers. Its work on optimizing collateral in finance improves lenders’ costs by 6 basis points compared with more conventional approaches, according to the company. Collateral optimization involves allocating assets to meet margin requirements, reduce costs and maximize returns.

IonQ, a quantum-computing company based in College Park, Md., typically uses simulated quantum computers during the early stages of a client engagement and actual quantum computers to validate results, according to Masako Yamada, IonQ’s director of applications development.

“We are exploring where quantum algorithms can benefit existing workflows in machine learning, chemistry and optimization," Yamada said. “The goal is to develop hybrid solutions that offer advantages over classical-only methods."

It is true that these early efforts provide only small glimpses at the full potential of quantum computing.

One of the great challenges of the field, and there are many, is that fragile qubits generate errors as they tackle problems, with the error rate increasing as the platforms get larger. Qubits are the basic units of quantum computation.

Google says Willow, the new quantum chip it announced this month, switches this dynamic, reducing errors with the addition of more qubits. It will be around three years before the error rate reaches the target, according to Google, and the company doesn’t expect its quantum systems to reach full scale until the end of the decade.

“I’ll say upfront, the vast majority of applications that people are excited about are going to really be unlocked with a fault-tolerant quantum computer," said Charina Chou, chief operating officer at Google Quantum AI. “That’s not where we are right now and we expect even more software development to happen at that stage."

Commercial use of Google’s quantum tech might still be too distant for some of its parent company’s investors. But for a certain group of early adopters with long-term development cycles—especially in areas such as finance, energy and life sciences, the same ones mentioned by Terra Quantum—the tech is close enough to start work.

Google also has healthy competition. This month, Illinois Gov. JB Pritzker said the Quantum and Microelectronics Park being developed in Chicago will be home to IBM’s Quantum System Two, the company’s most advanced quantum computer, which will be used to explore quantum applications across industries. IBM says it expects Quantum System Two in Chicago to be up and running in the coming year. It is currently running System Two in its research lab Yorktown Heights, N.Y., and plans to deploy another System Two next year in Japan with the RIKEN national research institute.

Another company, Palo Alto, Calif.-based startup PsiQuantum, says it will have the world’s first large-scale, fault-tolerant, commercially useful quantum computer up and running in Australia in 2027—and a second one in operation at Chicago’s park in 2028.

Quantum computing’s potential applications include helping to produce safer, more effective drugs, said Stratton Sclavos, chief business officer of PsiQuantum. Or it could help design fertilizers that are both cheaper and less destructive to the environment, he said.

“I’m not trying to speed up your simulation that, you know, works perfectly, well," Sclavos said. “What I’m trying to do is give you a simulation of a thing you can’t simulate today."

While that goal is still years away from being fulfilled, some companies are getting a very real sneak peek right now.

Write to Steven Rosenbush at steven.rosenbush@wsj.com