Entangling gates with performance close to fundamental limits

Oxford和NIST Boulder离子阱小组都证明了具有世界纪录的99.9%保真度的双量子位纠缠门，显著高于任何其他量子位平台[Ballance等人，Phys.Rev.Lett. 2016年，Gaebler等人，Phys.Rev.Lett. 2016年]。然而，该误差仍然比由拉曼光子散射设定的准基本极限高约一个数量级。牛津大学最近也在离子阱中实现了最快的（480 ns）纠缠门[Schäfer等人，Nature 2018]，其速度类似于最近在硅器件中展示的双量子位门。该项目的宏伟目标是最大限度地减少剩余的技术误差，将最佳保真度推向99.99%的光子散射极限。学生还将研究演示通过控制驱动门的激光场的光学相位和/或减少Lamb-Dicke参数来进一步加速门速度的新想法的实用性。该项目属于EPSRC Quantum设备组件和系统主题的福尔斯

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