Hannover 2020 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 24: Quantum Information (Quantum Computing)
Q 24.5: Talk
Wednesday, March 11, 2020, 12:15–12:30, e001
High-fidelity two-qubit gates using robust pulsed dynamical decoupling — Patrick Barthel1, Jorge Casanova2, •Patrick Huber1, Theeraphot Sriarunothai1, Martin Plenio3, and Christof Wunderlich1 — 1Department Physik, Universität Siegen, 57068 Siegen, Germany — 2Department of Physical Chemistry, University of the Basque Country UPV/EHU, Apartado 644, 48080 Bilbao, Spain — 3Institut für Theoretische Physik, Albert-Einstein-Allee 11, Universität Ulm, 89069 Ulm, Germany
Continuous or pulsed dynamical decoupling (DD) has been successfully used to extend the coherence time of qubits, for example in trapped atomic ions. A recently proposed, novel DD sequence is presented that not only extends the coherence time, but also results in a tunable two-qubit phase gate with high fidelity. Using both motional modes of a two-ion crystal, it allows for higher gate speeds than comparable single-mode gates [1]. We report on the experimental realization of a π/4-gate with a fringe contrast up to 99(2)%, applying this sequence on a set of two 171Yb+ ions in a linear Paul trap using microwave driving fields. The interaction between motional and internal qubit states necessary for conditional quantum logic is provided by magnetic gradient induced coupling (MAGIC) [2]. We demonstrate the applicability of the sequence for Controlled-NOT operations and the creation of Bell states, as well as its robustness to errors in Rabi frequency, trap frequency and to ion temperature.
[1] I. Arrazola et al., Phys. Rev. A 97, 052312 (2018)
[2] T. Sriarunothai et al., Quantum Sci. Technol. 4 (2019) 015014