Yale University researchers have developed a high-frequency version of a device known as an acoustic resonator that they say could advance the field of quantum computing and information processing.

Professor of Electrical Engineering and Physics Hong Tang and his research team did this with a piezo-optomechanical device that achieves what is known as a "strong coupling” between two systems: a superconducting microwave cavity and a bulk acoustic resonator system. With a strong coupling, the device achieves an exchange of energy and information between the microwave and mechanical resonator systems in a way that exceeds the dissipation, or diminishing energy, of each of the individual systems. That way, information doesn’t get lost.

Schematic of the piezo-electromechanical device. Image source: Yale UniversityA unique feature of the system is that it operates at the frequency of 10 gigahertz. An advantage of a high-frequency system is that it allows for a high signal-processing speed, says Xu Han, a Ph.D. student in Tang’s lab.

Another advantage is that the high frequency makes it easier to observe quantum phenomena in experiments. In lower-frequency devices, the system has to be cooled to extreme temperatures to overcome thermal noise, which comes from random vibrations from the environment that scramble the signal.

According to Han, one of the potential applications is information storage. “If you have a good coupling and exchange between the systems, then you can store information from the microwave domain in the mechanical domain,” he says.

Although the experiments weren’t done under quantum conditions, the researchers say that the high-frequency piezo-electromechanical device is compatible with superconducting qubits—the unit of information analogous to digital bits in conventional computing. That potentially could mean an important step toward hybrid quantum systems, which bridge the world between classical and quantum mechanics.

Han is now building on the technology to develop a device that uses the mechanical system to convert information from the microwave domain to the optical.