In a matter of months, two different experimental groups had taken on the challenge to create the time crystals in the laboratory. One of the teams fired laser pulses at a train of ytterbium atoms that produced oscillations in the atoms’ properties, at different intervals from the pulses. This meant that the ytterbium atoms were behaving as a time crystal.
The other team focused on an entirely different system, consisting of impurities in a diamond crystal. They used microwaves to disturb the impurities at well-defined intervals, and observed the same type of time-crystal oscillations as the first team. At last, time crystals had been created and Wilczek’s main ideas proven true.
The prediction, realisation and discovery of time crystals opens a new chapter in quantum mechanics, with questions about the properties of this newly found state of matter and whether time crystals might occur in nature.
The symmetry-breaking properties of ordinary crystals have lead to the creation of phononic and photonic metamaterials, deliberately designed materials that selectively control acoustic vibrations and light that can be used to boost the performance of prosthetics, or to increase the efficiency of lasers and fibre-optics. So the time symmetry-breaking properties of time crystals will likely find their way into equally novel fields, such as chrono-metamaterials for quantum computing, which uses the inherent properties of atoms to store and process data.
The story of time crystals started with a beautiful idea by a theoretical physicist, and now has culminated its first chapter with conclusive experimental evidence after a mere five years. Far from coming to an end as scientists prove their big theories, it seems physics is more alive than ever.