Speaker: Cyril Laplane
Title: Harnessing atomic forces for quantum optomechanics with levitated nanocrystals
Harnessing quantum effects at any scale invariably requires isolating the quantum object of interest as much as possible, while keeping exquisite control over it. Levitated mesoscopic particles, with their intrinsic low coupling to the environment, are ideally suited as hybrid quantum platforms of mesoscopic size and mass [1,2]. In vacuum, the only coupling to the environment is the levitation field itself, resulting in a mechanical oscillator with a very high quality factor. Furthermore, control over almost all the motional degrees of freedom is possible . These systems have the potential for a whole new range of specific applications, with quantum advantage, such as inertial sensors for navigation and gravimetry.
Optical levitation usually relies on the interaction of light and the ‘bulk’ polarisability of the nanoparticle itself. Here we explore the possibility of harnessing the polarisability of electronic resonances of atoms. When embedded in nanocrystals, these quantum polarisabilities contribute to the total optical forces . This effect becomes particularly relevant for ensembles of active centres . We investigate these resonant optical forces on levitated rare-earth-ion-doped nanocrystals. This advanced control over the motion of the particle opens the possibility to access new effects for the quantum manipulation of mesoscopic systems.
 Tebbenjohanns, F. et al. Nature 595, 378–382 (2021)
 Magrini, L. et al. Nature 595, 373–377 (2021)
 Gieseler, J. et al. Phys. Rev. Lett. 109, 103603 (2012)
 Juan, M. L. et al. Nat. Phys. 13, 241–245 (2017)
 Prasanna Venkatesh, B. et al. Phys. Rev. Lett. 120, 033602 (2018)
Bio: I graduated from the University of Lyon in 2012 with a Master in Nanoscale Engineering. I then moved in Geneva to do a PhD in the Group of Applied Physics under the supervision of Prof. Nicolas Gisin, where I developed and studied solid-state quantum memories for light based on rare-earth-ion-doped solids with application in quantum communication. I joined Macquarie University at the end of 2017 to work on nanodiamonds optical sorting. Since then I also have been expanding my research activities, using optical tweezers in microfluidic chips to study different nanoparticles in wet environment and developing a new optical trapping setup in vacuum for levitodynamics studies. In 2020, I was awarded a Sydney Quantum Academy postdoctoral fellowship to investigate and develop new quantum sensors based on levitated nanocrystals. My project will expand the capabilities of these levitated systems and will explore their potential applications for inertial sensing, gravimetry and probing the boundaries between quantum and classical physics.
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