On the experimental side, we have performed magnetic levitation experiments of ferromagnets at Leiden and Southampton. We have performed optical levitation experiments at Southampton. We have implemented vibration isolation systems to reduce the effect of mechanical noise on the levitated systems. We are building a payload for a demonstration of optically levitated sensors in space. We have used the levitation systems to perform weak force measurements. We did experiments at Leiden on two-mass gravity on the attoNewton level and together with partners at Trento on magnetic field measurements at the femtoTesla level. We are working on using optical levitation systems to generate non-Gaussian states by a modulation protocol using cooling, squeezing, and non-linear effects.
On the theory side, we studied the dynamics of a levitated nanoparticle transitioning between harmonic and double-well potentials, considering thermal effects. We characterized the system thermodynamically using Wehrl entropy and explored time-dependent control in regimes with comparable quantum effects and thermal noise. Squeezing the initial state mitigated noise, we quantitatively assessed unitary and dissipative contributions to the control protocol. Regarding alternative (non-relativistic) models to quantum gravity, we studied: the Schrödinger-Newton equation, which posits a classical nature for gravity, causing deviations from standard quantum mechanics; the Károlyházy model for gravitational decoherence; the Diósi-Penrose model, according to which gravity induces the wave function collapse.
