Towards laser-free dynamical cooling via exchange with a pre-cooled ion

The ability to transport ions within a future quantum information processor is expected to play a key role in enabling small subsets of ions to be addressed without crosstalk. This need for transport may necessitate subsequent recooling, as it can be difficult to transport ions without heating them up to the detriment of subsequent quantum operations. Furthermore, anomalous heating increases ion temperatures both during transports and in stationary potentials. As the number of transport operations increases, current recooling methods impose a bottleneck on the speed of trapped-ion quantum information processors [1]. We are currently working towards the experimental implementation of a novel laser-free dynamical cooling scheme [2]. We plan to merge a hot ion with a precooled coolant ion (drawn from a cold reservoir) into the same harmonic potential. During and after the merge, a controllable energy exchange takes place [3], transferring motional quanta from the hot ion to the coolant. After the exchange, the ions are separated and the coolant ion is returned to the cold reservoir. In this work, we lay out our experimental progress, as well as the challenges ahead.

1. Pino, J. M., et al. Demonstration of the Trapped-Ion Quantum CCD Computer Architecture. Nature 592, 209–213 (2021).

2. Sägesser, T., et al. Robust Dynamical Exchange Cooling with Trapped Ions. New Journal of Physics 22 073069 (2020).

3. Brown, K. R., et al. Coupled Quantized Mechanical Oscillators. Nature 471, 196–199 (2011).