Companies like Vector Atomic and Infleqtion are helping the military harness quantum technologies to develop underground sensing, secure communications and alternatives to GPS.

If a spy balloon floating high above the U.S. is an example of a 19th-century tech war, think of quantum as the near future.

The Pentagon has for years been searching for new ways to use quantum physics to wage war, whether it’s developing more powerful computers, backstopping GPS, strengthening the security of communications or creating means of surveillance that could better detect submerged submarines and underground bunkers. There’s urgency: China is investing heavily in furthering these capabilities, too.

Take GPS, for example. In the event of armed conflict between the U.S. and China, one of the first things both sides would target would be the other country’s global positioning system. Imagine the chaos on the ground and the confusion in the sky without it.

Researchers are developing quantum-enhanced navigation systems that would enable ships and aircraft to stay on course in the event of a GPS outage, as well as guide missiles to their targets more accurately. Part of that involves creating more accurate atomic clocks, since GPS is at heart a timing system — calculating the difference in time between satellites and receivers on the ground. The technology will be ready within five years, said Michael Hayduk, a deputy director of the Air Force Research Laboratory.

“This will change the world in rather remarkable ways, and you don’t have to wait too long for it,” William Clark, a physicist and vice president at Infleqtion, a startup that’s one of the leaders in the field, told Forbes.