Levitated Magnet

Since 2023 August, I have joined the NVs-mechanics project with graduate students Frankie Fung (BA, UChicago ‘18), DaLi Schaefer (BA, UMich ‘18) and Trisha Madhavan (BA, Princeton ‘21).

Interfacing spins and mechanical degrees of freedom allows for a variety of applications and experimental observations. For example, one can deterministically entangle pairs of spins through their coherent coupling with the dynamics of a resonator, even for large spin-spin distance separations and thermal resonator states. Additionally, the resonator could be cooled close to the quantum ground state by bringing a strongly coupled bath of spins into resonance, introducing the possibility of single phonon experiments and quantum state preparation of a mesoscopic object.

Our other mechanical resonator setup consists of a ~ 10 um ferromagnetic microsphere levitated over a superconductor. The flux-pinning from the SC traps the magnet in three dimensions (center-of-mass modes) as well as its dipole orientation (librational modes). These center-of-mass modes have been shown to reach the kHz regime. Additionally, quality factors of more than 10^6 have been demonstrated. We couple these center-of-mass modes to an NV by placing a bulk diamond beneath the SC. Our previous works are:

• Rusconi, Cosimo Carlo, et al. “Hybrid architecture for engineering magnonic quantum networks.” Physical Review A 100.2 (2019): 022343.

• Gieseler, Jan, et al. “Single-spin magnetomechanics with levitated micromagnets.” Physical Review Letters 124.16 (2020): 163604.

A nice article to read.

We are currently working on increasing the quality factor of the motion and increasing the coupling strength.