Time Crystals Revolutionize Quantum Computing Potential

Researchers at Aalto University have made a significant breakthrough by successfully connecting a time crystal to an external system, a first for the field. This advancement, detailed in a study published on October 16, 2023, in the journal Nature Communications, could enhance the capabilities of quantum computers and sensors, potentially transforming the landscape of quantum technology.

Understanding Time Crystals

A time crystal, as conceptualized by Frank Wilczek, the 2012 Nobel Laureate in Physics, represents a unique quantum system characterized by a perpetual motion that requires no external energy input. These systems exhibit a repeating pattern in time rather than space, maintaining their lowest energy state while remaining in constant motion. Time crystals were experimentally confirmed to exist in 2016, but until now, they had not been linked to any external systems.

The research team, led by Jere Mäkinen, an Academy Research Fellow, has demonstrated how a time crystal can be integrated into an optomechanical system. This integration paves the way for the development of highly accurate sensors and advanced memory systems for quantum computers. Mäkinen states, “Perpetual motion is possible in the quantum realm so long as it is not disturbed by external energy input, such as by observing it. That is why a time crystal had never before been connected to any external system. But we did just that and showed, also for the first time, that you can adjust the crystal’s properties using this method.”

Breakthrough Methodology

The researchers utilized radio waves to pump magnons into a Helium-3 superfluid, which was cooled to near absolute zero. Magnons are quasiparticles that can behave as individual particles in groups. When the radio wave pump was turned off, the magnons formed a time crystal that maintained its motion for an unprecedented duration of up to 10^8 cycles, equivalent to several minutes, before its motion began to fade.

During the fading process, the time crystal connected to a nearby mechanical oscillator, influenced by the oscillator’s frequency and amplitude. Mäkinen elaborates, “We showed that changes in the time crystal’s frequency are completely analogous to optomechanical phenomena widely known in physics. These are the same phenomena that are used, for example, in detecting gravitational waves at the Laser Interferometer Gravitational-Wave Observatory in the U.S.”

Future Implications for Quantum Technology

The implications of this research are vast, particularly for quantum computing and sensing. Mäkinen notes that time crystals can last significantly longer than current quantum systems, which could allow them to enhance memory systems in quantum computers. “The best-case scenario is that time crystals could power the memory systems of quantum computers to significantly improve them,” he adds. Furthermore, these crystals could serve as frequency references in extremely high-sensitivity measurement devices, improving their accuracy and reliability.

The work was conducted at the Low Temperature Laboratory, part of OtaNano, Finland’s national research infrastructure dedicated to nano-, micro-, and quantum technologies. This research not only advances our understanding of quantum systems but also opens new avenues for technological innovation in the rapidly evolving field of quantum computing.