Green Todd J, Biercuk Michael J
ARC Centre for Engineered Quantum Systems, School of Physics, The University of Sydney, New South Wales 2006 Australia.
Phys Rev Lett. 2015 Mar 27;114(12):120502. doi: 10.1103/PhysRevLett.114.120502. Epub 2015 Mar 25.
We present a scheme designed to suppress the dominant source of infidelity in entangling gates between quantum systems coupled through intermediate bosonic oscillator modes. Such systems are particularly susceptible to residual qubit-oscillator entanglement at the conclusion of a gate period that reduces the fidelity of the target entangling operation. We demonstrate how the exclusive use of discrete shifts in the phase of the field moderating the qubit-oscillator interaction is sufficient to both ensure multiple oscillator modes are decoupled and to suppress the effects of fluctuations in the driving field. This approach is amenable to a wide variety of technical implementations including geometric phase gates in superconducting qubits and the Molmer-Sorensen gate for trapped ions. We present detailed example protocols tailored to trapped-ion experiments and demonstrate that our approach has the potential to enable multiqubit gate implementation with a significant reduction in technical complexity relative to previously demonstrated protocols.
我们提出了一种方案，旨在抑制通过中间玻色子振荡器模式耦合的量子系统之间纠缠门中不忠实度的主要来源。此类系统在门操作周期结束时特别容易产生残留的量子比特 - 振荡器纠缠，这会降低目标纠缠操作的保真度。我们展示了如何仅通过调节量子比特 - 振荡器相互作用的场的相位离散偏移，就足以确保多个振荡器模式解耦，并抑制驱动场波动的影响。这种方法适用于多种技术实现方式，包括超导量子比特中的几何相位门和囚禁离子的莫尔默 - 索伦森门。我们给出了针对囚禁离子实验的详细示例协议，并证明我们的方法有可能实现多量子比特门的实现，相对于先前展示的协议，技术复杂度显著降低。
