Tailoring the van der Waals Interaction with Rotation.

We report a systematic procedure to engineer the van der Waals force between levitated nanoparticles in high vacuum by setting them into a fast rotation. By tuning the rotation frequency close to a polaritonic resonance, we can significantly enhance the van der Waals attraction. In addition, for frequencies slightly beyond resonance, rotation can change the nature of the interaction from attraction to repulsion. Rotational Doppler shifts effectively modify the frequency-dependent polarizability of the nanoparticles, thereby reshaping their mutual interaction. As a concrete and realistic example, we consider spinning barium strontium titanate nanoparticles at state-of-the-art rotation frequencies and demonstrate a modification of the force within the sensitivity of current experimental techniques.