Description
The quantum state of a levitated nanoparticle can be achieved by cooling the center-of-mass motion to
the ground-state. Delocalizing this state to increase position uncertainty to a scale comparable to the particle's
physical size is yet to be realized. Expansion protocols for this are limited primarily by decoherence due to
photon recoil, dephasing and shot-to-shot noise. This suggests expansion methods should be developed for so-
called dark, non-optical, potentials and run on platforms that are resilient to stray fields and mechanical
instabilities. We develop a dynamic shuttling protocol that emulates a wide double-well dark potential to
engineer both squeezing and non-Gaussian dynamics of the quantum state of a levitated nanoparticle. The
desired static potential is decomposed into an equivalent potential due to a system of electrodes driven by time-
dependent signals. Applying the signals to the system of electrodes produces time-dynamic shuttling that
matches the phase-space evolution, depicted in the figure below. This numerical method can determine time-
dependent signals to drive the effective dynamics of many types of static potentials, providing control over the
trajectory's time-of-flight and displacement independent of the particle's mass and charge. For example, the
pseudopotential of a Point Paul trap is one half of a double-well potential but any trajectory displacing the
particle from the potential null to explore the anharmonicities introduces increasing micromotion. Our dynamic
shuttling protocol can exactly replicate the desired double-well potential evolution without introducing the
micromotion inherent to the RF-driven potential. This provides adaptability around experimental hardware
limitations to engineer the desired amount of squeezing and non-gaussian dynamics produced. We then test
this protocol with the thermal state of a silica nanoparticle. Our work demonstrates advancement towards
preparing macroscopic quantum spatial superpositions.
| I am the presenting author | Yes |
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