New phase of matter known as ‘crystals of time’ observed interacting for the very first time

For the very first time, scientists have witnessed the interaction of a new phase of matter known as the ‘crystals of time’.

The discovery, published in Materials from nature, can lead to applications in quantum information processing because time crystals automatically remain intact – coherent – under varying conditions. The protection of coherence is the main difficulty hindering the development of powerful quantum computers.

Dr Samuli Autti, senior author from Lancaster University, said: “Controlling the interaction of two time crystals is a major achievement. Before that, no one had observed two time crystals in the same system, let alone seen them interact.

“Controlled interactions are the number one item on the wish list of anyone looking to harness a time crystal for practical applications, such as quantum information processing.”

The ultra-low temperature rotary cryostat from Aalto University. Credit: Aalto University / Mikko Raskinen

Time crystals are different from a standard crystal – like metals or rocks – which is made up of atoms arranged in a pattern that repeats regularly in space.

First theorized in 2012 by Nobel Laureate Frank Wilczek and identified in 2016, time crystals exhibit the bizarre property of being in constant motion and repeated over time despite the lack of external input. Their atoms are constantly oscillating, rotating or moving in one direction and then the other.

An international team of researchers from Lancaster, Yale, Royal Holloway London and Aalto University in Helsinki observed temporal crystals using helium-3, a rare isotope of helium with a missing neutron. The experiment was carried out at Aalto University.

They cooled the superfluid helium-3 to less than a ten-thousandth of a degree absolute zero (0.0001K or -273.15 ° C). The researchers then created two temporal crystals inside the superfluid and allowed them to touch each other.

Scientists observed the two time crystals interacting and exchanging constituent particles flowing from one time crystal to another, and vice versa – a phenomenon known as the Josephson effect.

Time crystals have great potential for practical applications. They could be used to improve current atomic clock technology – complex timepieces that keep time as accurate as possible. They could also improve technologies like gyroscopes and systems that rely on atomic clocks like GPS.

Reference: “AC Josephson effect between two superfluid time crystals” by S. Autti, PJ Heikkinen, JT Mäkinen, GE Volovik, VV Zavjalov and VB Eltsov, August 17, 2020, Materials from nature.
DOI: 10.1038 / s41563-020-0780-y