Speaker
Description
Multi-species trapped-ion quantum computing provides a promising route to overcoming challenges associated with motional heating and competing operational requirements in quantum devices. We present progress towards the implementation of sympathetic cooling within a mixed-species platform using ytterbium and barium ions in a microwave-driven trapped-ion architecture.
Our group uses ytterbium ions as data qubits [1], encoded in hyperfine ground states, while barium ions act as auxiliary cooling ions. As direct laser cooling of the ytterbium qubits during computation would destroy stored quantum information, cooling is achieved via coupling to shared motional modes of co-trapped barium ions. We demonstrate the integration of barium ions into an existing ytterbium system and investigate their performance as a sympathetic cooling resource.
Cooling of the barium ions will be investigated via doppler cooling on the 493nm S ½ <-> P ½ transition alongside an EIT cooling protocol [2] and the resulting reduction in motional excitation of the coupled ytterbium ions is to be characterised using coherence time measurements and resolved sideband thermometry of the Yb ions.
The system is implemented in a X-junction surface trap enabling flexible reconfiguration of ion chains for cooling and future gate operations. Barium ions are loaded via pulsed laser ablation and we assess the compatibility of this approach with existing ytterbium loading techniques.
[1] Weidt, S., et al. ''Trapped-ion quantum logic with global radiation fields.'' Physical Review Letters 117.22 (2016): 220501. https://doi.org/10.1103/PhysRevLett.117.220501
[2] Lechner, Regina, et al. 'Electromagnetically-Induced-Transparency Ground-State Cooling of Long Ion Strings'. Physical Review A, vol. 93, no. 5, May 2016, p. 053401. DOI.org (Crossref), https://doi.org/10.1103/PhysRevA.93.053401
| Academic level | PhD student |
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