“Time crystals” sounds like some sort of wibbly-wobbly-timey-wimey Dr Who nonsense. But they just might be very real – and very useful. They won’t fire up a sonic screwdriver, but they could potentially be used in quantum computers.
Normal crystals might be termed “space crystals”: that is, they repeat their atomic self-organisation in space, in microscopic structures called crystal lattices. Crystal lattices repeat and extend their structures in the three dimensions familiar to us as “space”. But, as Einstein taught us, “space” is really “spacetime”. Time is a fourth dimension.
So a time crystal is one that extends its crystal lattice in a regular, repeated pattern in time. The structure of time crystals changes periodically through time: they will stay in one configuration for a while, then flip to another, back and forth in an endless cycle. Time crystals are different from normal crystals at the atomic level. Their atoms spin periodically, changing directions as a pulsating force flips them, quite literally, like an old grandfather clock. A time crystal can be regarded as an assemblage of quantum particles that are continually changing and never reaching a steady state.
Once nudged into oscillation, might time crystals reverberate indefinitely? A Harvard experiment indeed produced a crystal that glowed as a result of its periodic energy reverberations after it was activated. But, as the laws of thermodynamics dictate, friction caused the reverberations to lose energy as heat. That was the end of the time crystal.
Well, so much for that. Time crystals sound cool and all – but so what?
Firstly, it is believed that a deeper understanding of time crystals will lead to breakthroughs in the accuracy of atomic clocks, gyroscopes and magnetometers, all vital technologies in the modern world. But more intriguing applications might lie in the field of quantum computing. Current quantum computers have to operate at cold – very cold – temperatures. Near absolute zero.
Time crystals could enable stable quantum systems at far higher operating temperatures than at present. Quantum computing might finally be practicable.
In a study conducted at the National Institute of Informatics (NII), Nippon Telegraph and Telephone Corporation (NTT), Osaka University, the Japanese-French Laboratory of Informatics (JFLI) and Tokyo University of Science, scientists developed a method to use time crystals to simulate massive networks with very little computing power.
Using time crystals after their approach, scientists are now planning to explore different quantum systems. They aim to propose real applications for embedding exponentially large complex networks in a few qubits or quantum bits.
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