Speaker
Description
We propose a new sub-Doppler cooling scheme in trapped ion crystals in Paul traps which utilizes a Sisyphus-like cooling mechanism to simultaneously cool all the motional modes of the crystal.
We use a hollow tweezer, tuned near resonance with the transition from the qubit manifold to a short-lived excited manifold, to generate a state-dependent tweezer potential. This introduces a position dependent quench rate for the qubit states. The cooling scheme is completed by using a microwave field to drive the magnetic dipole transition between the qubit states, creating a Sisyphus-like cooling mechanism which is augmented by the position dependent effective lifetime.
We identify the optimal cooling parameters for one and two-ion crystals exactly, and use a variational ansatz to extract the cooling rate for larger ion crystals. We also show that this cooling scheme is relatively robust against tweezer pointing errors. Furthermore, the scheme allows for the entire crystal to be cooled sympathetically by adressing a single ion with the tweezer, while not destroying the internal qubit state of the other ions.
