A Novel Method Of Measuring Time

A new paper describes a novel way of measuring time. It involves no new scientific discoveries and is simply a clever engineer application of existing science. But it has the potential to be useful in a wide variety of scientific and engineering applications.

[A]ccording to researchers from Uppsala University in Sweden. . . . experiments on the wave-like nature of something called a Rydberg state have revealed a novel way to measure time that doesn't require a precise starting point.

Rydberg atoms are the over-inflated balloons of the particle kingdom. Puffed-up with lasers instead of air, these atoms contain electrons in extremely high energy states, orbiting far from the nucleus. . . . In some applications, a second laser can be used to monitor the changes in the electron's position, including the passing of time. These 'pump-probe' techniques can be used to measure the speed of certain ultrafast electronics, for instance.

From here citing Marta Berholts, et al., "Quantum watch and its intrinsic proof of accuracy" 4 Phys. Rev. Research 043041 (October 18, 2022). The abstract of the paper is as follows:

We have investigated the rich dynamics of complex wave packets composed of multiple high-lying Rydberg states in He. A quantitative agreement is found between theory and time-resolved photoelectron spectroscopy experiments. We show that the intricate time dependence of such wave packets can be used for investigating quantum defects and performing artifact-free timekeeping. The latter relies on the unique fingerprint that is created by the time-dependent photoionization of these complex wave packets. These fingerprints determine how much time has passed since the wave packet was formed and provide an assurance that the measured time is correct. Unlike any other clock, this quantum watch does not utilize a counter and is fully quantum mechanical in its nature. The quantum watch has the potential to become an invaluable tool in pump-probe spectroscopy due to its simplicity, assurance of accuracy, and ability to provide an absolute timestamp, i.e., there is no need to find time zero.