Ultracold clocks could reveal how quantum physics changes time

What does the passage of time look like a really quantum object? The best clocks in the world could soon be able to answer this question, testing how time can stretch and move in the quantum field and allow us to probe areas of unexplored physics.

The idea that the passage of time can change or expands comes from the special theory of the relativity of Albert Einstein. Einstein has shown that an object is approaching the speed of light, time seems more slowly than for a stationary observer. He extended this idea with his general theory of relativity, showing a gravitational field has the same break effect. Igor Pikovski at the Stevens Institute of Technology in New Jersey and his colleagues wanted to understand if something similar could happen in the microscopic quantum world, as measured by an ultracold clock made from ions.

“Any experience that we have to date always feels something like classic time, time that has nothing to do with quantum mechanics,” explains Pikovski. “We realized that there is a diet where with ionic clocks, this description simply fails,” he says.

These clocks are made from thousands of cooled ions at temperatures close to absolute Zero by being struck by lasers. At these extreme temperatures, quantum states of ions and electrons inside can be very precisely controlled with electromagnetic forces. Consequently, ticks of ion clocks are defined by these electrons oscillating several times between two specific quantum states.

Because their functioning is dictated by the laws of quantum mechanics, these clocks were the ideal framework for Pikovski and its colleagues to explore how relativistic and quantum effects can mix to affect clock ticks. Pikovski says that researchers have now identified several cases where it should happen.

An example stems from the fact that quantum physics hates nothing. Instead of being able to remain absolutely motionless and frozen, even at extremely low temperatures, quantum objects must fluctuate, gain random or lose energy. The team’s calculations have shown that these fluctuations could expand the measure of the time of a clock. The effect would be very low, but most likely observable with clock experiences of existing ions.

The researchers also mathematically modeled what would happen if the ions of a clock were “pressed” to produce a “superposition” of several quantum states. They found that the TIC-TAC, as determined by the electrons in the ions, would inextricably become connected to the movement of the ion itself-the states of the ions and the electrons would become quantum tangled. “Normally, in experiences, you have to play tips to design a tangle. The fascinating thing here is that it comes whether you wanted it or not, ”explains Christian Sanner, member of the team at the Colorado State University.

Pikovski says that it is intuitive that a quantum object in a superposition of states could not feel a single sense of time, but the effect was never observed in an experience. This should be possible in the near future, he said.

The member of the Gabriel team is witching at the Stevens Institute of Technology said that the next step is to add another crucial modern physics – gravity. Ultracold clocks can already detect time dilation due to tiny changes in the resistance of gravitational traction of the earth, for example when you are noted even a few millimeters, but exactly how this effect would mix with the inherent quantification of the clock is an open question.

“I think this is actually quite reasonable to do with the technology we currently have,” said David Hume at the US National Institute of Standards and Technology in Colorado. He says that the biggest challenge would be to prevent tiny clock environmental disturbances that master the effects that the Pikovski team. In case of success, such experiences would allow researchers to probe the phenomena of physics that they could never before, even if quantum theory and the theory of special relativity are two pillars which have long resisted a large part of contemporary physics, he says.

“Experiences like this are exciting because they force these theories to confront themselves in an area where there is a chance that we can learn something new,” said Alexander Smith at Saint Anselm College in New Hampshire.