Researchers unveil new application for high-precision quantum sensors

According to foreign media reports, Oriol Romero-Isart, a researcher at the Institute of Quantum Optics and Quantum Information at the Austrian Academy of Sciences, the University of Innsbruck and the Department of Theoretical Physics, and a team led by Romain Quidant of ETH Zurich have proposed a new concept for high-precision quantum sensors.

Image credit: University of Innsbruck

The researchers propose that the motion fluctuations of nanoparticles trapped in microscopic optical resonators can be significantly reduced to below zero-point motion by exploiting the system's fast unstable dynamics.

Mechanical quantum squeezing reduces the uncertainty of motion fluctuations below the zero-point motion. This has been experimentally demonstrated in the past using micromechanical resonators in the quantum state. Now, the researchers are proposing new methods, in particular custom-made suspended mechanical systems.

"The experiments demonstrate that a properly designed optical cavity can be used to quickly and strongly squeeze the motion of suspended nanoparticles," says Katja Kustura from the group of Oriol Romero-Isart in Innsbruck. In an optical resonator, light bounces between mirrors and interacts with the suspended nanoparticles. This interaction can lead to dynamic instabilities.

"In the current study, we show how the unstable dynamics of a mechanical oscillator inside an optical cavity can give rise to mechanical squeezing by properly controlling these instabilities," Kustura said.

This study expands the use of optical cavities as mechanical quantum squeezers and suggests a new path for suspended optomechanics beyond quantum ground state cooling. Microresonators can therefore provide an interesting new platform for the design of quantum sensors, for example, for satellite missions, self-driving cars and seismology.