Paper detail

Proposal for macroscopic delocalisation of a large mass in a RF trap

Engineering coherent spatial superpositions of levitated large masses is an ongoing challenge. Borrowing from recent experimental work, we consider a charged mass of hundreds of nanometers size (``nanoparticle'') co-trapped with an ion in a Paul trap, and propose a scheme to manipulate its spatial state through the Coulomb interaction with the ion. We focus on the achievable delocalisation, only sketching the other challenges of the protocol (initial cooling, preservation of coherence for long-enough times, and detection). We prove that our scheme can displace coherently the nanoparticle by a few nanometers, with state-of-the-art parameters. Though smaller than the nanoparticle's size, this is much larger than the wavefunction of the trap's ground state. Thus the co-trapping scheme is in principle able to demonstrate macroscopic delocalisation of a charged nanoparticle.