Physics: 'Quantum Radio' Breakthrough Could Save Your Life in a Fire, Flood or Earthquake

Firefighters battle a 7-alarm fire on January 2 in the Bronx borough of New York City. Spencer Platt/Getty Images

For the first time, physicists have demonstrated that "quantum radio" could function in situations where regular radio signals are no match for high levels of interference—underwater, underground, in remote landscapes or even collapsed buildings.

Researchers from the National Institute of Standards and Technology and the department of physics at the University of Colorado, Boulder, arrived at the breakthrough by experimenting with very low-frequency radio. The lower a signal's frequency, the farther it travels, but at the expense of the precision afforded with higher frequencies.

The researchers built a direct-current magnetometer that detects the "spin" of certain atoms using polarized light. Because the atoms are highly sensitive and respond quickly, the resulting quantum sensors would be able to enhance very low-frequency radio with the best of both worlds—precise signals at an ideal bandwidth. A paper detailing the work was published in the Review of Scientific Instruments.

Physicist Dave Howe aligns a laser beam to pass through a tiny glass cell of rubidium atoms inside the cylindrical magnetic shield. National Institute of Standards and Technology

"Our idea was to find a sensor that's the most sensitive and also still practical that could be used to extend the range," corresponding author Vladislav Gerginov told Newsweek. "Quantum sensors meet that criteria." Quantum sensors also meet the criteria of being small, cheap, and relatively simple to operate.

Atomic magnetometers are normally used for measuring the Earth's natural magnetic fields, not for picking up communications signals. No one's ever studied quantum physics in the context of low-frequency radio before; it's an entirely new field of research. The one they built wasn't miniaturized—it's a research tool, not a prototype, so there wouldn't have been much point—but Gerginov said it could be made about the size of a matchbox.

Standard communication techniques often fail because our usual radio signals can't penetrate very far through complex materials like water or rock. Quantum radio, however, isn't subject to such limitations.

"Often, firefighters fall victim to the fact that they cannot find their way out or communicate even if they are less than 100 feet from safety," Gerginov said. "In such harsh environments, with debris and metal objects, it's impossible to use normal electromagnetic signals like radio."

Quantum radio stands to change that. It does have at least one intrinsic restriction; the communications range is pretty small, no more than maybe 2,000 or 3,000 feet. That said, it works in situations where traditional radio has a range of zero feet, so the advantages are self-evident. The next step is developing improved transmitters.

"We're not trying to replace existings radios," Gerginov said. "We simply want to add an extra method for when everything else fails."