Department of Physics, Pennsylvania State University, University Park, PA, USA.
Science. 2016 Jun 24;352(6293):1562-5. doi: 10.1126/science.aaf2581.
Although the quality of individual quantum bits (qubits) and quantum gates has been steadily improving, the number of qubits in a single system has increased quite slowly. Here, we demonstrate arbitrary single-qubit gates based on targeted phase shifts, an approach that can be applied to atom, ion, or other atom-like systems. These gates are highly insensitive to addressing beam imperfections and have little cross-talk, allowing for a dramatic scaling up of qubit number. We have performed gates in series on 48 individually targeted sites in a 40% full 5 by 5 by 5 three-dimensional array created by an optical lattice. Using randomized benchmarking, we demonstrate an average gate fidelity of 0.9962(16), with an average cross-talk fidelity of 0.9979(2) (numbers in parentheses indicate the one standard deviation uncertainty in the final digits).
尽管单个量子位（qubit）和量子门的质量一直在稳步提高，但单个系统中的量子位数增加得相当缓慢。在这里，我们展示了基于目标相移的任意单量子比特门，该方法可应用于原子、离子或其他类似原子的系统。这些门对寻址束的不完美性高度不敏感，并且交叉干扰很小，从而极大地提高了量子比特的数量。我们在一个由光晶格创建的 5x5x5 的三维阵列中，对 48 个单独靶向的站点进行了串联门操作。通过随机基准测试，我们证明了平均门保真度为 0.9962(16)，平均交叉干扰保真度为 0.9979(2)（括号中的数字表示最后一位数字的一个标准差不确定度）。
