Sick of missing appointments by milliseconds because of inaccurate atomic clocks? Researchers say they could use quantum physics to create a timekeeper so accurate it could help explain some of the mysteries of time itself. The "quantum superclock" would involve multiple atomic clocks, each in its own satellite orbiting the Earth and each carrying pairs of linked particles entangled in such a way that "measuring a property of one of them instantaneously determines the same property for the other," Nature explains—a phenomenon known as "quantum entanglement" that Albert Einstein called "spooky action at a distance," notes Forbes. In the case of these satellites, a central satellite would fashion its clock particles in an entangled state, then extend the entanglement to another satellite, and so on, until the quantum network is created.
The linked clock would be far more accurate than anything that exists today, allowing for precise linking of financial markets, better space navigation, and even the detection of subtle shifts in space and time. The researchers say that in addition to measuring time, the quantum timepiece could measure the Earth's terrain so accurately that somebody digging a tunnel under the US-Mexican border could be spotted from space, Science News reports. Much research remains to be done before such a superclock can become a reality, but "we're trying to be a little bit visionary," says Harvard physicist Eric Kessler. "All the building blocks have been demonstrated in principle, and we want to show what might lie ahead if all these fields merge together." In the meantime, the US has unveiled what it says is the most accurate clock in the world.