Manovitz Tom, Rotem Amit, Shaniv Ravid, Cohen Itsik, Shapira Yotam, Akerman Nitzan, Retzker Alex, Ozeri Roee
Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot 76100, Israel.
Racah Institute of Physics, The Hebrew University of Jerusalem, Jerusalem 91904, Givat Ram, Israel.
Phys Rev Lett. 2017 Dec 1;119(22):220505. doi: 10.1103/PhysRevLett.119.220505. Epub 2017 Nov 29.
Engineering entanglement between quantum systems often involves coupling through a bosonic mediator, which should be disentangled from the systems at the operation's end. The quality of such an operation is generally limited by environmental and control noise. One of the prime techniques for suppressing noise is by dynamical decoupling, where one actively applies pulses at a rate that is faster than the typical time scale of the noise. However, for boson-mediated gates, current dynamical decoupling schemes require executing the pulses only when the boson and the quantum systems are disentangled. This restriction implies an increase of the gate time by a factor of sqrt[N], with N being the number of pulses applied. Here we propose and realize a method that enables dynamical decoupling in a boson-mediated system where the pulses can be applied while spin-boson entanglement persists, resulting in an increase in time that is at most a factor of π/2, independently of the number of pulses applied. We experimentally demonstrate the robustness of our entangling gate with fast dynamical decoupling to σ_{z} noise using ions in a Paul trap.
量子系统之间的工程纠缠通常涉及通过玻色子媒介进行耦合，在操作结束时，该媒介应与系统解耦。这种操作的质量通常受环境噪声和控制噪声的限制。抑制噪声的主要技术之一是动态解耦，即通过以高于噪声典型时间尺度的速率主动施加脉冲。然而，对于玻色子介导的门，当前的动态解耦方案要求仅在玻色子与量子系统解耦时执行脉冲。这种限制意味着门时间增加了sqrt[N]倍，其中N是所施加脉冲的数量。在此，我们提出并实现了一种方法，该方法能够在玻色子介导的系统中实现动态解耦，其中在自旋-玻色子纠缠持续存在时可以施加脉冲，从而使时间增加最多为π/2倍，且与所施加脉冲的数量无关。我们使用保罗阱中的离子通过快速动态解耦实验证明了我们的纠缠门对σ_z噪声的鲁棒性。
