Determining the passage of time in a world of ticking clocks and swinging pendulums is a simple case of counting the seconds between “then” and “now.”
Experiences revealed Researchers from Uppsala University in Sweden have learned about the wave-like nature of something called the Rydberg state, for a new method for measuring the time that does not require an exact starting point.
Rydberg’s atoms are hyperinflated balloons of the particle kingdom. Inflated by a laser instead of air, these atoms contain electrons in extremely high energy states, orbiting far from the nucleus.
Of course, not every laser pump needs to blow an atom to cartoonish proportions. In fact, lasers are routinely used to tickle electrons at higher power states for a variety of uses.
In some applications, a second laser can be used to monitor changes in the electron’s position, including the passage of time. For example, These “pump-probe” techniques can be used to measure the speed of some ultra-fast electronics.
Inducing atoms into Rydberg states is a useful trick for engineers, not least when it comes to designing new components for quantum computers. Needless to say, physicists have gathered a great deal of information about the way electrons move when pushed into the Rydberg state.
The mathematical rulebook behind this wild game of Rydberg’s electron roulette is referred to as the Rydberg wave packet. And just like actual waves in a pond, having more than one Rydberg wave packet rippling in space creates interference, resulting in unique patterns of ripples. Throw enough Rydberg’s wave packets into the same atomic pool, and these unique patterns will account for the characteristic time it takes for the wave packets to match each other.
The research included measuring the results of laser-excited helium atoms and matching their results with theoretical predictions.
Physicist Marta Berholtz of Uppsala University in Sweden, who led the team, explained: “If you use a counter, you have to set zero. You start counting at some point. The benefit of that is that you don’t have to start the clock — you just have to look at the overlap structure and say” Well, 4 nanoseconds passed.
A guidebook for advanced Rydberg wave beams can be used along with other forms of pump-probe spectroscopy that measure events on a small scale, when they are now and then less obvious, or simply inconvenient to measure.
Most importantly, none of the fingerprints require time and update to serve as a starting and stopping point for time. It would be like benchmarking an unknown runner’s race against a number of competitors running at set speeds.
By looking for the signature of overlapping Rydberg states amid a sample of the pump probe’s atoms, technicians can observe the timestamp of events as small as 1.7 trillionths of a second.
Future quantum clock experiments could replace helium with other atoms, or even use a laser pulse of different energies, to extend the evidence of timestamps to a wider range of conditions.
The research was published in the journal Physical Review Research.
