Within the emerging field of Quantum Optomechanics, it has become possible in
recent years to establish a quantum interface between light and the motion of an
engineered mechanical oscillator, and to observe such effects as motional
sideband asymmetry, radiation pressure shot noise, and ponderomotive squeezing.
These achievements are now being extended towards applications and fundamental
research. The possibility to manipulate motion at the quantum level opens new
avenues such as sensing technologies with unprecedented sensitivities, encoding
quantum information in ultrahigh-quality nanomechanical systems, and engineering
macroscopic quantum states for testing of fundamental quantum physics. I will
describe my recent work with optomechanical photonic crystals, demonstrating
quantum measurement techniques that evade quantum backaction noise [1,2] and laser
cooling of motion down to record-level 92% ground state occupation . I will show
how to extend these results with related methods that generate mechanical squeezed
states, to realize sensing of force and displacement beyond the standard quantum limit.
In addition I will describe my recent theoretical proposal for generating superposition
(cat) states in a macroscopic oscillator , that directly builds upon these techniques.
 Shomroni et al., Phys. Rev. X 9, 041022 (2019)
 Shomroni et al., Nat. Commun. 10, 2086 (2019)
 Qiu*, Shomroni* et al., Phys. Rev. A 100, 053852 (2019)
 Qiu*, Shomroni* et al., arXiv:1903.10242
 Shomroni et al., arXiv:1909.10624