A new theoretical paper shows that trapped-ion optical clocks could directly probe subtle effects at the intersection of quantum mechanics and general relativity — including the superposition of proper times and entanglement induced by time dilation.

By leveraging the extreme precision of these clocks, researchers demonstrated an experimental route to exploring phenomena that go beyond what current atomic clocks can access, even as today’s devices already account for relativistic time dilation.

Read more in Physical Review Letters.

High-precision clocks based on quantum systems will work in a regime where a quantum description of proper time might be necessary.