SAMOP 2021 – scientific programme

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QI: Fachverband Quanteninformation

QI 1: Implementations: Atoms, Ions and Photons

QI 1.5: Talk

Monday, September 20, 2021, 12:15–12:30, H4

Tunable magnetic quadrupole for MAGIC-based quantum information processing in a planar electrode ion trap — •Ivan Boldin, Elham Esteki, Bogdan Okhrimenko, and Christof Wunderlich — University of Siegen, Siegen, Germany

Magnetic gradient induced coupling (MAGIC) is an approach to quantum information processing with trapped ions, where all coherent operations with qubits are carried out with microwave-frequency electromagnetic fields. This approach requires a strong static magnetic field gradient along the chain of trapped ions. Such a static gradient can either be created by electric currents or by permanent magnets. Electric currents are tunable, but it is hard to reduce the current noise to a sufficiently low level. Permanent magnets can provide a strong field gradient with low noise, but the field cannot be tuned. We have come up with a solution to the abovementioned challenge: a system that is free from electrical currents during quantum logic operations, and which creates a fully tunable strongly inhomogeneous magnetic field. This is achieved by the use of a permanent magnet quadrupole made of moderate coercivity material (AlNiCo) that can be magnetized (and demagnetized) by short current pulses. We present the results of experimental characterization of our novel type of magnetic quadrupole. Using trapped Yb ions as a magnetic field sensor, we demonstrate a maximum gradient of 116 T/m and the tunability of the field. In addition, we present the results of the investigation of the coherence properties of the trapped-ion based qubits, depending on the magnetic field gradient.