Speaker
Description
A major driving force of the field of levitodynamics — the levitation
and control of microobjects in vacuum — is the possibility of generating
macroscopic quantum states of the center-of-mass motion of a levitated
nanoparticle. Not only can these states help address questions about
the interplay between gravity of quantum physics or the nature of
wavefunction collapse, but their mere existence would prove the validity
of quantum mechanics at regimes of mass 4 orders of magnitude higher
than the current record. Recent demonstrations of ground-state motional
cooling and quantum control along one motional direction (1D) show that
such quantum regime of levitated nanoparticles is within experimental
reach. Still, the generation and certification of macroscopic quantum
states requires to answer crucial fundamental questions, for instance:
can one break the seemingly fundamental limitation which allows to only
feedback-cool efficiently one of the three motional degrees of freedom?
How to protect motional quantum states from decoherence? and how to
generate the strong nonlinearity needed to observe purely quantum
(Wigner-negative) states?
In my talk, I will discuss our team’s theoretical effort to answer
these questions. I will introduce our recently developed theoretical
formalism describing the quantum interaction between light and a
trapped dielectric sphere of arbitrary size. I will show how we
quantitatively predict that (i) 3D ground-state feedback cooling is
possible for particles beyond the point-dipole approximation (ii) laser-
induced motional decoherence can be fully suppressed by using
squeezed light and (iii) shifting from harmonic to double-well potentials
allows to generate detectable Wigner negativities within the motional
coherence lifetime. Our work sets the theoretical basis of 3D levitated
optomechanics and provides the tools to design future macroscopic
quantum physics experiments.