Here’s how time crystals really work

No, they don’t violate thermodynamics

Not a time crystal. Maxim Bilovitskiy

Lately, it has been in the news that Google quantum computing researchers (and numerous university researchers) have created the first true time crystal in a quantum computer. While it sounds like something out of a Marvel movie, time crystals are a real phenomenon. The crystals flip back and forth between two states periodically in time which mimics the regularity of the spacing of molecules in a crystal.

There have been a lot of misconceptions thrown about whether time crystals violate the laws of thermodynamics: conservation of energy or the tendency for entropy to increase. Some have even suggested that they achieve the dream of perpetual motion.

This is false and shows an ignorance of the fine print attached to the laws of thermodynamics as well as the real requirements for achieving a time crystal.

First off, time crystals are not perpetual motion machines in that (a) they cannot do mechanical work and (b) they do not exist in a ground or equilibrium state. Rather, they are quantum systems that do no work and cannot reach a ground state.

Second, time crystals do not violate the law of conservation of energy. They do not gain or lose energy but move without energy loss. This is generally possible in small systems…