A team led by Marta Berholts, an experimental physicist at Tartu University, have created a very different type of “quantum watch” that "does not require an initial “time zero” reference point to make its time measurements.

Figure 1: A very different type of “quantum watch” to measure accurate time.

Figure 1 shows that “the quantum watch provides a fingerprint representing a specific time, and hence only requires interaction when initiating and reading out the time,” Marta Berholts explained. [1]

“A quantitative agreement is found between theory and time-resolved photoelectron spectroscopy experiments,” the team wrote, who says they were able to demonstrate that unravelling the complex behaviours of these wave packets can not only help to shed light on various quantum “defects,” but more broadly, can also be used in achieving “artifact-free timekeeping.”

According to a paper outlining the team’s results, the individual wave packets they observed create their own unique “fingerprint” due to the photoionization they undergo, each of which is uniquely time-dependent.

“These fingerprints determine how much time has passed since the wave packet was formed,” the authors say, “and provide an assurance that the measured time is correct.” The researchers have likened the resulting unique method of timekeeping to being a quantum watch. [2]

Their research involved measuring the results of laser-excited helium atoms and matching their findings with theoretical predictions to show how their signature results could stand in for a duration of time.

"If you're using a counter, you have to define zero. You start counting at some point," physicist Marta Berholts. "The benefit of this is that you don't have to start the clock – you just look at the interference structure and say 'okay, it's been 4 nanoseconds.”

Importantly, none of the fingerprints require a then and now to serve as a starting and stopping point for time. By looking for the signature of interfering Rydberg states amid a sample of pump-probe atoms, technicians could observe a timestamp for events as fleeting as just 1.7 trillionths of a second.

Future quantum watch experiments could replace the helium with other atoms, or even use laser pulse of different energies, to broaden the guide book of timestamps to suit a broader range of conditions. [3]

References:

1. https://www.vice.com/en/article/dy7kyv/scientists-invent-quantum-watch-a-mind-bending-new-way-to-measure-time
2. https://thedebrief.org/quantum-watch-helps-physicists-reveal-a-completely-new-way-to-measure-time/
3. https://www.sciencealert.com/scientists-just-discovered-an-entirely-new-way-of-measuring-time

Cite this article:

Hana M (2023), A Quantum Stopwatch Measures the Time with Complete Accuracy, AnaTechmaz, pp.108