26th Australian Institute of Physics Congress and the Australian and New Zealand Conference on Optics and Photonics

Reconstructing the phonon distribution of trapped ions out of the Lamb-Dicke regime

Not scheduled

20m

Belinda Hutchinson Building (The University of Sydney )

Contributed Oral AIP | Quantum Science and Technology (QST)

Speaker

Prachi Nagpal (University of Sydney)

Description

Deterministic preparation and reconstruction of high-energy Fock states have potential applications in quantum metrology [1], computing [2], simulation [3], and the study of fundamental physics. In trapped ions, common methods to characterise an arbitrary Fock distribution employ first-order sideband interactions [4] of the Jaynes-Cummings type, causing them to fail at high energies due to the Rabi frequency degeneracies in that regime. Hence, reliable Fock reconstruction beyond the Lamb-Dicke limit remains an open question. Here, we present a protocol to overcome this by generalising the driving interactions to any order and using composite pulses that implement narrow-passband filters [5] in rabi-frequency-space. We experimentally demonstrated the protocol in a Paul trap by preparing large Fock states (N > 100) and reconstructing them with high fidelity.

1. X. Deng et al., Nat. Phys. 20, 1874–1880 (2024)
2. D. Gottesman et al., Phys. Rev. A 64, 012310 (2001)
3. R. J. MacDonell et al., Chem. Sci. 12, 9794 (2021)
4. D. Leibfried et al., Phys. Rev. Lett. 77, 4281 (1996)
5. B. T. Torosov et al., Phys. Rev. A 92 (2015)