For the first time ever, scientists have witnessed the interaction of a new phase of matter known as ‘time crystals’.
The discovery, published in Natural materials, can lead to applications in quantum information processing, because time crystals automatically remain intact – coherent – in changing conditions. Protecting coherence is the main difficulty that hinders the development of powerful quantum computers.
Dr. Samuli Autti, lead author of Lancaster University, said: ‘Monitoring the interaction of double crystals is a major achievement. Before this no one had observed two time crystals in the same system, let alone seen interaction.
“Managed interactions are the number one item on the wish list of anyone looking for a time crystal for practical applications, such as processing quantum information.”
The ultra-low temperature rotating cryostat at Aalto University. Credit: Aalto University / Mikko Raskinen
Time crystals are different from a standard crystal – such as metals or rocks – which consists of atoms arranged in a regularly repeating pattern in space.
First theoretically identified in 2012 by Nobel Prize winner Frank Wilczek and in 2016, time crystals exhibit the bizarre property of being in constant, repetitive motion over time despite no external input. Their atoms oscillate, spin, or move first in one direction, and then the other.
An international team of researchers from Lancaster, Yale, Royal Holloway London, and Aalto University in Helsinki observed time crystals using Helium-3, which is a rare isotope of helium with one missing neutron. The experiment was conducted at Aalto University.
“Controlling the interaction of two time crystals is a great achievement.” – Dr. Samuli Autti
They cool excess helium-3 to within ten thousandths of a degree of absolute zero (0.0001K or -273.15 ° C). The researchers then made two time crystals within the abundance, and let them touch.
The scientists saw the two time crystals interacting and alternating from existing particles flowing from one time crystal to another, and back – 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 hold the most accurate time we can possibly reach. They could also improve technology such as gyroscopes, and systems that rely on atomic clocks, such as GPS.
Reference: “AC Josephson effect between two abundant time crystals” by S. Autti, PJ Heikkinen, JT Mäkinen, GE Volovik, VV Zavjalov and VB Eltsov, 17 August 2020, Natural materials.
DOI: 10.1038 / s41563-020-0780-y
