When matter crystallizes, its atoms spontaneously organize themselves into the rows, columns and stacks of a three-dimensional lattice. An atom occupies each “lattice point,” but the balance of forces between the atoms prevents them from inhabiting the space between. Because the atoms suddenly have a discrete, rather than continuous, set of choices for where to exist, crystals are said to break the spatial symmetry of nature — the usual rule that all places in space are equivalent. But what about the temporal symmetry of nature — the rule that stable objects stay the same throughout time?

The Nobel Prize-winning physicist Frank Wilczek often develops outlandish theories that eventually enter the mainstream. “Of course not everything I do works,” he says. Image: Frank Wilczek

Wilczek mulled over the possibility for months. Eventually, his equations indicated that atoms could indeed form a regularly repeating lattice in time, returning to their initial arrangement only after discrete (rather than continuous) intervals, thereby breaking time symmetry. Without consuming or producing energy, time crystals would be stable, in what physicists call their “ground state,” despite cyclical variations in structure that scientists say can be interpreted as perpetual motion.

“For a physicist, this is really a crazy concept to think of a ground state which is time-dependent,” said Hartmut Häffner, a quantum physicist at the University of California at Berkeley. “The definition of a ground state is that this is energy-zero. But if the state is time-dependent, that implies that the energy changes or something is changing. Something is moving around.”

How can something move, and keep moving forever, without expending energy? It seemed an absurd idea — a major break from the accepted laws of physics. But Wilczek’s papers on quantum andclassical time crystals (the latter co-authored by Alfred Shapere of the University of Kentucky) survived a panel of expert reviewers and were published in Physical Review Letters in October 2012. Wilczek didn’t claim to know whether objects that break the symmetry of time exist in nature, but he wanted experimentalists to try to make one.

This is rather mind blowing:

You know how a crystal is a group of atoms spaced in repeating patterns with gaps of space between them? A time crystal would be a group of atoms that rearranges its configuration at periodic intervals of time.

More:

http://www.reddit.com/r/science/comments/1df2se/nobel_prize_winning_physicist_proposes_experiment/

Mmm looks nice, but without experiment it's just maths and philosophy. : )

Math + Philosophy = NOT Science. 

Needs more science.

Hacker News thread: https://news.ycombinator.com/item?id=5634903