The research team uses time crystals as quantum computer controls

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• Researchers at the University of the Chinese Academy of Sciences have used a time crystal to improve the stability of quantum states in a quantum computer.
• The researchers note that this may be the first practical application of a time crystal.
• Time crystals were first theorized in 2012 by Frank Vilcek.

A team of researchers from the University of the Chinese Academy of Sciences has used a unique time crystal — a new state of matter — to improve the stability of quantum states in a quantum computer, marking a significant advance in the field of quantum computing. ArXiv paper and reported in New Scientist.

The approach, led by Biao Huang, centers on establishing the Greenberger-Horn-Zeilinger (GHZ) state, a complex quantum state that represents large-scale entanglement of qubits, the equivalent of bits in traditional computing.

Nobel laureate Frank Vilcek first theorized the concept of periodic crystals in 2012, sparking controversy due to their perpetual oscillation between two configurations without any energy input. In other words, seemingly defying the laws of physics, time crystals can always switch between two states in a regular pattern, requiring no force to keep moving. It is like a clock

Despite initial skepticism, several research groups have successfully created time crystals in laboratory settings, including quantum computers. Periodic crystals exhibit a unique pattern of oscillation over time, similar to how atoms arrange themselves in three-dimensional space to form regular crystals.

In this experiment, the researchers used a unique timing crystal as a control mechanism to preserve GHZ levels in their quantum computer, which consists of qubits made from tiny circuits capable of conducting electricity without resistance. These qubits may exist in quantum superposition, analogous to Schrödinger's cat thought experiment, where the cat is simultaneously alive and dead until its state is observed.

Think of it as a control knob for a quantum computer, the new scientist explained.

GHZ levels are critical for pushing the boundaries of quantum physics and developing quantum computing and communication technologies. However, as more qubits are entangled, they become increasingly unstable, with past experiments demonstrating the challenges of preserving their unique properties amid small perturbations. By using a unique timing crystal, the team was able to create a „safe house” to protect the GHZ state, achieving a less weak configuration of 36 qubits, compared to the previous unstable large state of up to 60 qubits.

Applying microwave pulses to qubits not only induces their quantum properties to oscillate and form a time crystal, but also reduces disturbances that normally disrupt the GHZ state. According to Biao Huang of the Chinese Academy of Sciences' Kavli Institute for Theoretical Sciences, this will mark the first practical use of a unique time crystal.

„We used the structure of a discrete time crystal to build a 'safe house' to shelter weak GHZ states,” Huang told New Scientist. „As far as we know, this is the first practical application of a unique time crystal. Our work tells people that time crystals are not only conceptually interesting, but also have practical value.

Experts in the field, including Francisco Machado of Harvard University and Mario Gren of the Max Planck Institute of Light in Germany, told New Scientist that the experiment represents an amazing technical achievement and its contribution to the advancement of quantum computing technologies. This research not only demonstrates the feasibility of stabilizing complex quantum states, but also opens up new ways to use time crystals and other quantum phenomena in practical applications.

ArXiv is a preprint server, which means the paper is not technically peer-reviewed.