Time crystals: One of the weirdest ideas in physics [View all]

[n2doc]

Physics is defined by its symmetries, from thermodynamics laws like the conservation of mass and energy, to the principle that the universe is basically the same all over. Symmetry can also suggest some truly bizarre ideas. One of those ideas is time crystals.
The definition of a crystal is simple enough - it's any solid whose constituent parts are arranged in an orderly, repeating pattern extending out in all three spatial dimensions. Although crystals themselves are defined by their symmetrical arrangement, they actually represent a form of what's known as spontaneous symmetry breaking in closed systems.

The idea here is that if you have a bunch of free atoms whizzing around, the overall system can display symmetry. But if those atoms suddenly come together to form a crystal, the overall symmetry of the system has been reduced onto one particular subgroup, namely the crystal. The overall spatial symmetry has been been broken, but the periodicity that defines the crystal's structure means it hasn't been entirely lost.

While that may be a bit theoretical, it's all fairly straightforward. The intriguing question is one that is often asked of physical phenomena - if this process exists in the three spatial dimensions, could it also occur in the dimension of time as well? That's the question currently being investigated by MIT physicist Frank Wilczek, who won the 2004 Nobel Prize along with David Gross and H. David Politzer for their work on the strong nuclear force.
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http://io9.com/5886651/time-crystals-one-of-the-weirdest-ideas-in-physics