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Comment by krapp | Hacker News Reader

apparently yes, but because it's in a low energy state, it's impossible to extract any energy from it and do work (otherwise it would be a perpetual motion machine.)

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It's interesting it is a perpetual motion machine, but it works only as long as you don't use it.

Any atomic nucleus with orbiting electrons fulfills that requirement, you could loosely call those time crystals too.

Their half life for most stable atoms is so long that perpetual applies for most practical uses of the word.

Which makes me wonder if these time crystals have a half-life too.

Electrons do not orbit atomic nuclei in the quantum description of atoms. Instead, in the lowest energy state the electron wave function is spread out in a sphere around the nucleus, and this wave function stays constant in time. Almost all quantum systems do something like this in the ground state, which shows why the time crystal is something new and interesting.

It must be able to tunnel into some other structure. The half-life is defined by how much energy it needs to "melt" as the article says.

The universe has a perverse sense of humor.

right, now i'll have to read the article to understand why there is no energy loss :)

it does seem to be breaking some rules.. but I guess that's the achievement here. Intuitively there should be some concept of friction/heat loss but maybe on this scale things are different. Maybe it could be exploited as a battery? A way of capturing energy into a stable kinetic "state". (Like a flywheel..)

Moving doesn't implement energy loss automatically. When things are set in motion, they will continue to move infinitely unless interfered by outside forces.

Right, but physical movement within a material without loss due to friction implies some kind of mechanical superconductor.. I mean, that's a pretty cool concept.

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