The age-old quest to pinpoint the dividing line between classical and quantum physics has long intrigued scientists. In a new study released today, researchers unveil an innovative platform that may finally shed light on this elusive boundary.
Quantum physics dictates the behaviour of particles at the tiniest scales, giving rise to phenomena like quantum entanglement, where entangled particles exhibit interconnected properties beyond the reach of classical physics.
While quantum research helps bridge gaps in our understanding of the physical world, the minuscule dimensions at which quantum systems operate pose challenges for observation and study.
In recent decades, physicists have successfully observed quantum effects in progressively larger objects, from subatomic particles to complex molecules. The emerging field of levitated optomechanics, focused on manipulating heavy micron-scale objects in a vacuum, aims to explore quantum phenomena in objects significantly larger than atoms and molecules.
However, as objects increase in mass and size, their interactions with the environment diminish delicate quantum features, resulting in classical behaviours. But a team led by Dr Jayadev Vijayan from The University of Manchester, in collaboration with scientists from ETH Zurich and theorists from the University of Innsbruck, has devised a groundbreaking approach to tackle this issue.
Their experiment at ETH Zurich, published in Nature Physics, involves placing particles between highly reflective mirrors to create an optical cavity. This setup allows photons scattered by each particle to bounce between the mirrors numerous times, increasing the likelihood of interaction with the other particle.
Johannes Piotrowski from ETH Zurich remarked, “With the mediation of the cavity, the optical interactions remain strong even over several millimetres, enabling coupling of micron-scale particles.”
The researchers also demonstrate the ability to finely tune interaction strength by adjusting laser frequencies and particle positions within the cavity. These findings not only advance our understanding of fundamental physics but also offer potential applications in sensor technology for environmental monitoring and navigation.
Dr Carlos Gonzalez-Ballestero from the Technical University of Vienna highlighted the benefits of levitated mechanical sensors in detecting gravitational forces and accelerations, making them valuable for various applications like climate research and navigation.
The team now plans to combine their new platform with quantum cooling techniques to explore quantum entanglement further. Success in entangling levitated nano- and micro-particles could bridge the gap between the quantum realm and everyday classical mechanics.
At The University of Manchester’s Photon Science Institute and Department of Electrical and Electronic Engineering, Dr Jayadev Vijayan’s team will continue their work in levitated optomechanics, harnessing interactions between multiple nanoparticles for quantum sensing applications.
