Motional quantum metrology in a Penning trap

¹ Área de Física Aplicada, Universidad Politécnica de Cartagena - 30202 Cartagena, Spain
² Departamento de Física Atómica, Molecular y Nuclear, Universidad de Granada - 18071 Granada, Spain
³ Centro de Investigación en Tecnologías de la Información y las Comunicaciones, Universidad de Granada 18071 Granada, Spain

^(a) javier.cerrillo@upct.es
^(b) danielrodriguez@ugr.es (corresponding author)

Received: 2 June 2021
Accepted: 8 June 2021

Abstract

We propose to measure the six motional frequencies of an unbalanced two-ion crystal in a Penning trap using a scheme that has been demonstrated in a quantum-metrology experiment with a single ion in a linear Paul trap. To study the feasibility, we derive the quantum Hamiltonian for the unbalanced crystal formed by a target and a sensor ion (⁴⁰Ca, and deduce characteristic coordinates , and , associated to the amplitudes of the displacement operator , and , respectively, when a dipolar time-varying field is applied. The final state after excitation is read out using rapid adiabatic passage. We also present the status of the 7 tesla open-ring Penning trap where first experiments on the ²³²ThCa crystal, cooled to the ground state, are foreseen in the short-term future. Finally, we underline possible experiments with this unique platform.