Chiral-coupling-assisted refrigeration in trapped ions
The tapped ions can be cooled close to their motional ground state, which is imperative in implementing quantum computation and quantum simulation. Here we demonstrate the capability of light-mediated chiral couplings between ions, which enables a superior cooling scheme exceeding the single-ion limit of sideband cooling. We present the chiral-coupling-assisted refrigeration in the target ion at the price of heating the others under asymmetric drivings, where its steady-state phonon occupation outperforms the lower bound set by a single ion. We further locate the optimal operation condition of the refrigeration and identify the parameter region where a faster rate of cooling emerges. Under an additional nonguided decay channel, the heating effect in the reciprocal coupling regime becomes suppressed and turns into cooling instead. Our results present a resource of collective chiral couplings which help surpass the bottleneck of cooling procedure in applications of trapped-ion-based quantum computer and simulator.