For the first time, physicists have captured a mysterious case on video.
Using a scanning transmission X-ray microscope, the research team recorded the oscillations of a time crystal made of magnones at room temperature. According to them, this is an important breakthrough in the study of time crystals.
“We have been able to show that such space-time crystals are much more robust and widespread than first thought,” said physicist Pawel Gruszecki of Adam Mickiewicz University in Poland.
“Our crystal condenses at room temperature and particles can interact with it – unlike in an isolated system. In addition, it has reached a size that can be used to do anything with this magnetic space-time crystal. It can result in many potential applications. “
Time crystals, sometimes also called space-time crystals, and which were only confirmed a few years ago, are as fascinating as the name suggests. They are much like ordinary crystals, but for an additional property.
In regular crystals, the constituent atoms are arranged in a solid, three-dimensional lattice structure – think of the atomic lattice of a diamond or quartz crystal. These repeating bars may differ in configuration, but within a given formation they do not move around much: they only repeat spatially.
In time crystals, the atoms behave a little differently. They turn, turn first in one direction and then the other direction. These oscillations – called ‘tik’ – are locked up regularly and frequently. Thus, where the structure of ordinary crystals repeats in space, it repeats crystals in time and time.
To study time crystals, scientists often use ultra-cold Bose-Einstein condensates from magnon brush particles. Magnones are not real particles, but consist of a collective excitement of the spin of electrons – like a wave propagating through a latticework.
The research team led by Gruszecki and his colleague, physics doctoral student Nick Träger of the Max Planck Institute for Intelligent Systems in Germany, did something different. They placed a strip of magnetic permalloy on an antenna through which they could transmit a radio frequency current.
That current produced an oscillating magnetic field on the strip, with magnetic waves moving on it from both sides; these waves stimulated the magnons in the strip, and these moving magnons are then condensed into a repeating pattern.
“We took the frequently repeating pattern of magnons into space and time, sent in more magnons and eventually dispersed,” Träger said. “So we were able to show that the time crystal can communicate with other brush particles. No one has been able to show it directly in an experiment yet, let alone in a video.”
The video above shows the magnetic wavefront propagating through the strip, filmed at up to 40 billion frames per second using the MAXYMUS X-ray microscope at the BESSY II synchrotron irradiation facility in Helmholtz Zentrum Berlin in Germany.
Time crystals must be stable and coherent over long periods of time, because they – theoretically – oscillate at their lowest possible energy state. The team’s research shows that driven magnonic time crystals can be easily manipulated, providing a new way to reconfigure time crystals. This can open up the state of affairs for a variety of practical applications.
“Classical crystals have a very broad field of application,” said physicist Joachim Gräfe of the Max Planck Institute for Intelligent Systems.
“If crystals can interact not only in space but also over time, we add another dimension of potential applications. The potential for communication, radar or imaging technology is huge.”
The research was published in Physical overview letters.