Optically Levitated Nanodumbbell Torsion Balance and GHz Nanomechanical Rotor

Abstract

Levitated optomechanics has great potential in precision measurements, thermodynamics, macroscopic quantum mechanics, and quantum sensing. Here we synthesize and optically levitate silica nanodumbbells in high vacuum. With a linearly polarized laser, we observe the torsional vibration of an optically levitated nanodumbbell. This levitated nanodumbbell torsion balance is a novel analog of the Cavendish torsion balance, and provides rare opportunities to observe the Casimir torque and probe the quantum nature of gravity as proposed recently. With a circularly polarized laser, we drive a 170-nm-diameter nanodumbbell to rotate beyond 1 GHz, which is the fastest nanomechanical rotor realized to date. Smaller silica nanodumbbells can sustain higher rotation frequencies. Such ultrafast rotation may be used to study material properties and probe vacuum friction.

Dynamically and thermally nonequilibrium fluctuation-electromagnetic interactions: Recent results and trends

“…, and the quantities with one and two dashes denote the relevant real and imaginary components. From (7) we see that lateral force is zeroed when 2 / π θ = , i.e. when the particle spin is oriented normal to the surface.…”

“…where 0 Ω and 0 θ are the initial values at 0 = t . Equation (7) implies that 2 / π θ ± → at the particle braking stage depending on the sign of 0 θ . Thus, for any initial orientation, the spin of particle tends to orient perpendicular to the surface, but the states 2 / π θ ± → are reached only at the full stop being asymptotically stable.…”

Prethermalization and Nonreciprocal Phonon Transport in a Levitated Optomechanical Array

“…The diameter of each nanosphere is 200 nm. The power of our trapping laser is mW, its waist is nm and its wavelength is nm . The polarization directions of all laser beam are chosen to be perpendicular to the array.…”

Encoding a qubit in a molecule

“…Though we have emphasized the potential applications to atoms and molecules, the same ideas can be applied to any quantized 3-dimensional rigid body that can be coherently manipulated. While there is a size limitation due to decoherence, we are on the cusp of entering the quantum regime for levitated nanoscale particles of helium [118], vaterite [119], diamond (alone [120] or doped [121]), and silicon [122][123][124], to name a few. Nanoparticles may seem to be unlikely candidates for quantum computing, but it would be interesting nonetheless to try to stabilize quantum superpositions of their orientational states (cf.…”