Unlike normal crystals such as diamonds, which repeat their atomic self-organization in space but do not show any regularity in time, time crystals self-organize and repeat their patterns in time - i.e., their structure changes periodically as time progresses. Such crystals, say the researchers, may be the next major leap in quantum network research.
"The exploration of time crystals is a very active field of research and several varied experimental realizations have been achieved," says Kae Nemoto, professor in the principles of informatics research division at the National Institute of Informatics (Japan) and author of a paper on the research. "Yet an intuitive and complete insight of the nature of time crystals and their characterization, as well as a set of proposed applications, is lacking. In this paper, we provide new tools based on graph theory and statistical mechanics to fill this gap."
In their work, the researchers examined how the quantum nature of time crystals - how they shift from moment to moment in a predictable, repeating pattern - can be used to simulate large, specialized networks, such as communication systems or artificial intelligence.
"In the classical world, this would be impossible as it would require a huge amount of computing resources," says Marta Estarellas of the National Institute of Informatics and a first authors of the paper. "We are not only bringing a new method to represent and understand quantum processes, but also a different way to look at quantum computers."
A video (below) shows how, over time, a perfect time crystal "melts" as the parameter of the quantum system changes. It can be seen how much the time crystal has melted by looking at the network. Interestingly, say the researchers, the time crystal does not melt equally - some parts are melting faster than others.
Quantum computers can store and manipulate multiple states of information, meaning they can process huge data sets with relatively little power and