(ORDO NEWS) — Determining the passage of time in our world of ticking clocks and swinging pendulums is a simple case of counting the seconds between “then” and “now.”
Down on the quantum scale of buzzing electrons, but “then” is not always predictable. Worse still, “now” is often blurred in a haze of uncertainty. In some scenarios, the stopwatch just doesn’t work.
A potential solution could be found in the form of quantum fog itself, according to a 2022 study by researchers at Uppsala University in Sweden.
Their experiments looking at the undulating nature of something called a Rydberg state opened up a new way of measuring time that doesn’t require a precise starting point.
Rydberg atoms are super-inflated balloons of the realm of particles. Inflated by lasers instead of air, these atoms contain electrons in extremely high energy states orbiting away from the nucleus.
Of course, not every pumping of a laser has to inflate an atom to cartoon size. In fact, lasers are commonly used to bring electrons into higher energy states for a variety of purposes.
In some applications, a second laser can be used to track changes in the electron’s position, including the passage of time.
These “pump-probe” methods can be used, for example, to measure the speed of some ultra-fast electronic devices.
Bringing atoms into Rydberg states is a handy trick for engineers, not least when it comes to designing new components. for quantum computers.
Needless to say, physicists have accumulated a significant amount of information about how electrons move when they are brought into the Rydberg state.
However, as quantum animals, their movements are less like sliding beads on tiny bills, and more like an evening at the roulette table, where every roll and bounce of the ball is compressed into a single game of chance.
The collection of mathematical rules behind this wild game of Rydberg electronic roulette is referred to as the Rydberg Wave Packet.
As with real waves, having multiple Rydberg wave packets oscillating in space creates interference, resulting in unique ripple patterns.
Throw enough Rydberg wave packets into the same atomic pond and each of these unique patterns will represent the specific amount of time it takes for the wave packets to evolve with each other.
These were the very “fingerprints” of time that the physicists behind this set of experiments set out to test, showing that they were consistent and reliable enough to serve as a form of quantum time stamping.
Their research involved measuring the results of helium atoms excited by a laser and comparing their results with theoretical predictions to show how the results of their signature could persist over a period of time.
“If you are using a counter, you must define zero. You start counting at some point,” physicist Martha Berholz of Uppsala University in Sweden, who led the team, told New Scientist in 2022.
“The advantage of this is that you don’t have to start the clock – you just look at the interference pattern and say, ‘OK, 4 nanoseconds have passed.’
A g Guide to Evolving Rydberg Wavepackets can be used in conjunction with other forms of pump-probe spectroscopy that measure events on a tiny scale when at times they are less clear or simply too inconvenient to measure.
Important. , none of the fingerprints require “then” and “now” to serve as the starting point and stopping point of time.
It’s like measuring the race of an unknown sprinter against several competitors running at a given speed.
By looking for signatures of interfering Rydberg states among the pump-probe atoms, technicians could observe the timestamp. for events as short as 1.7 trillionths of a second.
In future quantum clock experiments, helium could be replaced by other atoms, or even laser pulses of different energies could be used to expand the time stamp guide to cover a wider range of conditions.
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