Entangling gates with performance close to fundamental limits

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The Oxford and NIST Boulder ion trap groups have both demonstrated two-qubit entangling gates with world-record 99.9% fidelity, significantly higher than in any other qubit platform [Ballance et al. Phys.Rev.Lett. 2016, Gaebler et al., Phys.Rev.Lett. 2016]. However, the error is still about one order of magnitude above the quasi-fundamental limit set by Raman photon scattering. Oxford have also recently achieved the fastest (480ns) entangling gate in ion traps [Schäfer et al., Nature 2018] which is similar in speed to the recently-demonstrated two-qubit gates in silicon devices. This project will have the ambitious goal of minimizing the remaining technical errors, to push the best fidelity closer to the photon scattering limit of 99.99%. The student will also investigate the practicality of demonstrating new ideas for accelerating the gate speed further by control of the optical phase of the laser field that drives the gate, and/or reduction of the Lamb-Dicke parameter. This project falls under the EPSRC Quantum devices components and systems theme