Scientists Found an Entirely New Way of Measuring Time

In our world of moving timepieces and swinging pendulums, telling the difference between "then" and "now" is as easy as counting the seconds.

But 'then' can't always be predicted down at the subatomic size of buzzing electrons. Even worse, "now" frequently turns into an ambiguous cloud. In some situations, a timer will not be effective.

The shape of the quantum fog itself may hold the key to an answer, according to a 2022 investigation by scientists at Sweden's Uppsala University.

They discovered a novel method to quantify time that doesn't require an exact beginning point through experiments on the wave-like properties of something called a Rydberg state.

The overinflated balloons of the subatomic world are rydberg atoms. These atoms are inflated with lasers rather than air and have electrons orbiting far from the center in exceptionally high energy states.

Of course, not every laser pulse has to inflate an atom to ludicrous heights. In reality, a variety of applications frequently involve the use of lasers to nudge electrons into higher energy levels.

In some circumstances, a second laser can be used to keep track of time-related variations in the electron's location. These "pump-probe" methods can be used, for example, to gauge the speed of some rapid devices.

Engineers can use the ability to induce Rydberg states in atoms to their advantage, not least when creating innovative parts for quantum computers. It goes without saying that scientists have learned a lot about how electrons behave when pushed into a Rydberg state.

However, because they are quantum animals, their motions resemble an evening spent playing roulette rather than beads sliding around on a small abacus. Every ball roll and leap is combined into a single game of chance.

Rydberg wave packets are the mathematical playbook for this crazy game of Rydberg electron roulette.

Similar to real waves, interference occurs when multiple Rydberg wave packets are present in an area, producing different patterns of disturbances. If you combine enough Rydberg wave packets, the resulting distinct patterns will each reflect the unique amount of time it takes for the wave packets to develop in unison.

The purpose of this series of tests was to test these very "fingerprints" of time and demonstrate that they were reliable and consistent enough to be used as a type of quantum timestamping.

To demonstrate how their distinctive results could hold up over time, their study involved measuring the outcomes of laser-excited helium atoms and comparing their results with theory forecasts.

"Zero must be defined if a number is being used. At some point, you begin tallying, "In 2022, the team's leader and scientist Marta Berholts from the University of Uppsala in Sweden spoke with New Scientist about their findings.

The advantage of this is that you don't need to initiate the clock; instead, you can simply glance at the interference structure and note that 4 nanoseconds have passed.

A guidebook of changing Rydberg wave packets could be used in conjunction with other types of pump-probe spectroscopy that measure events on a small scale, when now and then are less obvious, or simply too cumbersome to measure.

It's important to note that none of the signatures necessitate a then and now to act as a temporal beginning and end. It would be comparable to evaluating a sprinter's performance against a group of opponents who were all racing at the same pace.

Technicians were able to determine a timestamp for events that happened in the course of just 1.7 trillionths of a second by searching for the hallmark of interfering Rydberg states among a collection of pump-probe atoms.

Future quantum watch tests might use laser pulses of various energies instead of helium or even other atoms to expand the timestamps' rulebook to accommodate a wider variety of circumstances.

This research was published in Physical Review Research.