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posted by janrinok on Monday July 06 2015, @06:42PM   Printer-friendly
from the is-it-made-of-kyber? dept.

From New Scientist

Ordinary crystals are three-dimensional objects whose atoms are arranged in regular, repeating patterns – just like table salt. They adopt this structure because it uses the lowest amount of energy possible to maintain.

Earlier this year, Frank Wilczek, a theoretical physicist at the Massachusetts Institute of Technology, speculated that a similar structure might repeat regularly in the fourth dimension – time.

Wilczek has also theorised that a working time crystal could be made into a computer, with different rotational states standing in for the 0s and 1s of a conventional computer.

The article includes a description (by Tongcang Li from the University of California, and others) of how such a time crystal could be built. Though it will be tricky because building the crystal will need temperatures close to absolute zero.

While Wilczek points out that the heat-death of the universe is, in principle, "very user friendly" for this kind of experiment because it would be cold and dark, there are other issues to consider.


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  • (Score: 4, Insightful) by dbe on Monday July 06 2015, @10:29PM

    by dbe (1422) on Monday July 06 2015, @10:29PM (#205867)

    So for the layman, would these crystal be a structure that would change over time and their geometry would periodically go back to the same shape?

    In is a sense would be analog to gliders structures in the game of life?
    https://en.wikipedia.org/wiki/Glider_(Conway's_Life) [wikipedia.org]

    -dbe

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  • (Score: 2) by Kell on Tuesday July 07 2015, @02:03AM

    by Kell (292) on Tuesday July 07 2015, @02:03AM (#205954)

    Regularly repeating configuration in time? It does sound suspiciously like an oscillator.

    --
    Scientists ask questions. Engineers solve problems.
    • (Score: 3, Insightful) by boristhespider on Tuesday July 07 2015, @07:16AM

      by boristhespider (4048) on Tuesday July 07 2015, @07:16AM (#206011)

      Yes - but they're in their lowest energy state. An oscillator will be driven, and then decay through friction etc when the driving force is removed. These are structures who exhibit motion in their "rest" state. Phrased slightly differently, they identify spatial crystals by a symmetry breaking - the equations of motion have greater symmetry than the solution. For a classical crystal, for instance, the equations of motion have translational symmetry but the crystal definitely doesn't.

      In the first paper ("Classical Time Crystals") they point out, "This seems perilously close to perpetual motion". Wilczek went to supercold regimes because it's reminiscent of superfluidity. In a quantum system you can conceivably get this kind of effect - you're free from thermal noise and you can build a system with large scale coherence.

      But yes, it does sound like an oscillator. Just a particular class of one. I like the analogy with the walkers in Conway's Game of Life.