Solid, liquid, gas and plasma -- these are the four main phases of matter. However during the 20th century, other extreme phases of matted has been introduced such as the Bose-Einstein condensates, quark-gluon plasma and neutron-degenerate matter. After repeatedly tweaking a group of ions, scientists create the very first non-equilibrium form of matter -- time crystal.
Time crystal extends the idea of a crystal to four dimensions and breaks time symmetry. Normal crystal such as diamonds has an atomic framework which repeats in space. Time crystals, however, suggests repeating such framework in time. The concept of time crystals was first proposed by Frank Wilczek in 2012. Last year, different groups of physicists at Princeton University and UC Santa Barbara's Station Q proved that time crystals could really be created.
Two groups of researchers from University of Maryland and Harvard University successfully created time crystals following the blueprint created by UC Berkeley physicist Norman Yao to create the very first time crystal. Their researches were both published with Yao as co-author. Yao explained that time crystals repeat in time as they are kicked periodically. He added that it is only the tip of the iceberg -- the first of a large group of materials which are intrinsically out of equilibrium.
"This is a new phase of matter, period, but it is also really cool because it is one of the first examples of non-equilibrium matter," Yao said according to Berkeley News. "For the last half-century, we have been exploring equilibrium matter, like metals and insulators. We are just now starting to explore a whole new landscape of non-equilibrium matter."
The researchers at University of Maryland used a conga line of 10 ytterbium ions. The electron spins of theses ions interact similarly to the qubit systems on as quantum computers. The ions are hit with laser to keep it out of equilibrium according to Science Daily. Meanwhile, the team at Harvard University used densely packed nitrogen vacancy centers in diamonds to set up its time crystal.
