Controlling non-classical mechanical states in a phononic waveguide architecture

Ingrid Fadelli is a writer for the website Phys.org.

Non-classical states of light are what most quantum computing technologies rely on. The theory of classical electromagnetism doesn't describe non-classical states because they can't be produced using conventional sources of light.

The states include squeezed states, entangled states and states with a negative wigner function. The ability to control the states of phononic systems, those involving acoustics and vibration, could open interesting possibilities for the development of new quantum technologies

There is a new strategy that could be used to achieve a high level of control. The strategy outlined in the paper could be applied to quantum technology.

The transmission of quantum information can be accomplished using optical fibers. They have been important components for both quantum technology and classical communication technology.

Simon Gr blacher, one of the researchers who carried out the study, said that it has the potential to change the field of quantum acoustics. The basis for full coherent control over traveling mechanical excitations will be formed by the use of low-loss phononic waveguides.

The aim of the recent work by Grblacher and his colleagues was to find a way to control non-classical mechanical states with individual phonons in a suspended Silicon structure. Physicists and engineers would be able to interact with quantum systems in new ways if they were able to carry out experiments in quantum acoustics.

"Acoustic waves are fundamentally different from the oscillation of single atoms or ion in traps, due to the associated large mass, their propagating character and the possibility to couple to a large variety of other quantum systems like quantum dots and superconducting qubits," Gr blacher said. It's crucial to realize hybrid quantum devices and transfer quantum information over heterogeneous networks.

Grblacher's research group has conducted many experiments in the past few years. They were able to create, store and detect single phonons in the past.

As part of their study, they designed and realized a first-of-its-kind phononic waveguide.

The propagation of non-classical mechanical states in the waveguide was verified by combining the source and detector for non-classical mechanical states with the waveguide. "These acoustic waves at GHz frequencies are guided in a highly confined nanoscale geometry, with long lifetimes, particularly at low temperatures, enabling the faithful transport of quantum states over centimeter distances on a chip."

Grblacher and his colleagues showed that the non-classical correlations emerging from the different times of the day are related. The non-classical correlations had a mechanical lifetime of around 100 s, which means that their system could theoretically be used to transmit single phonons over tens of centimeters.

The researchers found a way to realize a first-in-first-out quantum memory. It is possible that quantum acoustics and telecommunications could be applications for such a memory.

More information: Amirparsa Zivari et al, Non-classical mechanical states guided in a phononic waveguide, Nature Physics (2022). DOI: 10.1038/s41567-022-01612-0 Journal information: Nature Physics

There is a science network.