Researchers have succeeded in extending the life of time crystals, confirming the theoretical concept proposed by Frank Wilczek. This represents an important step forward in quantum physics.
A team from TU Dortmund University recently succeeded in producing an extremely durable time crystal that lives millions of times longer than could be shown in previous experiments. In doing so, they confirmed a very interesting phenomenon, which was postulated by Nobel laureate Frank Wilczek about ten years ago and which has already found its way into science fiction films. The results have now been published in Nature physics.
A pioneering achievement in time crystal research
Crystals, or more precisely, crystals in space, are periodic arrangements of atoms on large length scales. This arrangement gives the crystals their exquisite appearance, with smooth facets as in gemstones.
Since physics often treats space and time at the same level, for example in special relativity, Frank Wilczek, a physicist at the Massachusetts Institute of Technology (MIT) and Nobel laureate in physics, hypothesized in 2012 that in addition, for For crystals in space, there must also be crystals in time. For this to be the case, he said, one of its physical properties must begin to change spontaneously periodically over time, even though the system does not experience similar periodic interference.
Understanding time crystals
The possibility of the existence of such time crystals has been the subject of controversial scientific debate for several years – but it quickly reached cinemas: for example, the time crystal played a central role in the Marvel Studios film Avengers: Endgame (2019). From 2017 onwards, scientists have already succeeded on a few occasions in demonstrating a possible time crystal.
However, these systems – contrary to Wilczek's original idea – were subjected to temporal excitation with a specific periodicity, but then reacted with another period twice as long. A crystal that behaves periodically with time, even though the excitation is time-independent, i.e. constant, was only demonstrated in 2022 in a Bose-Einstein condenser. However, the crystal only lived for a few milliseconds.
Leap in time crystal longevity
Dortmund physicists led by Dr. Alex Grelich have now designed a special crystal made of indium gallium arsenide, in which nuclear spins act as a reservoir for the time crystal. The crystal is continuously illuminated so that the polarization of the nuclear spin is formed by interaction with the electron spin. It is precisely this nuclear spin polarization that spontaneously generates oscillations, the equivalent of a time crystal.
The state of the experiments at the moment is that the crystal has a lifespan of at least 40 minutes, which is 10 million times longer than has been proven so far, and will likely live much longer.
It is possible to vary the crystallization period over large scales by systematically changing the experimental conditions. However, it is also possible to move to areas where the crystal “melts”, i.e. loses its periodicity. These regions are also interesting, as chaotic behavior then emerges, which can be maintained for long periods of time. This is the first time that scientists have been able to use theoretical tools to analyze the chaotic behavior of such systems.
Reference: “Strong continuous time crystal in the nuclear electron spin system” by A. Greilich, NE Kopteva, AN Kamenskii, PS Sokolov, VL Korenev and M. Bayer, 24 January 2024, Nature physics.
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