It's time for time crystals to leave the lab and enter the everyday world, researchers say – and a new breakthrough suggests this might happen sooner rather than later.
Time crystals can exist for an arbitrarily long time at room temperature despite noise and energy loss, a team led by UC Riverside Assistant Research Professor Hossein Taheri has shown.
Time crystals are a recent discovery. Just like regular crystals are a repetition of structure in space, time crystals are a collection of many particles whose arrangement repeats in time. These peculiar objects have been observed in a variety of systems (even a children’s toy) but always under lab conditions.
As reported in the journal Nature Communications, the research team observed a time crystal not isolated from its environment. They created this all-optical time crystal by shooting two laser beams on a magnesium fluoride glass resonator one millimeter in diameter.
Using a technique called self-injection, the system can overcome energy dissipation that would lead to the time crystal breaking down. The approach appears to be robust when placed in a real-world setting.
“When your experimental system has energy exchange with its surroundings, dissipation and noise work hand-in-hand to destroy the temporal order,” Taheri, lead author, said in a statement. “In our photonic platform, the system strikes a balance between gain and loss to create and preserve time crystals.”
The interesting characteristic of time crystals is a sort of temporal symmetry breaking with respect to the force or energy that creates them. In this case, the laser pulses repeat at certain intervals to keep the system going. It is said that they have a specific period.
The time crystal, once created by these pulses, will also repeat, but its period is different from the period of the laser pulses – and that’s where the potential of the time crystals lies.
Given its repeating nature, applications for this type of technology might benefit from either specific frequencies or accurate time measurements. After all, frequency and time are mathematical inverses.
“We hope that this photonic system can be utilized in compact and lightweight radiofrequency sources with superior stability as well as in precision timekeeping,” added Taheri.
Could we soon have a watch that ticks thanks to a time crystal? Maybe not quite so soon – but this work puts us a step closer.