Parallel entangling operations on a universal ion-trap quantum computer
Parallel entangling operations on a universal ion-trap quantum computer
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DOI：
10.1038/s41586-019-1427-5
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发表时间：
2019-08-15
期刊：
影响因子：
64.8
通讯作者：
Monroe, C.
中科院分区：
文献类型：
--
作者：
Figgatt, C.;Ostrander, A.;Monroe, C.
量子计算机的电路模型由量子比特（qubit）之间的门操作序列组成，这些序列来自通用的离散操作家族（1）。执行并行纠缠量子门的能力在许多量子电路（2-4）以及整个算法（如Shor的因子分解算法（5））和量子模拟（6，7）中提供了效率增益。在诸如全加器和多控制Toffoli门之类的电路中，并行性可以通过分治技术（8）在总体执行时间上提供指数级改进。更重要的是，量子门并行性对于遭受空闲错误的量子位的容错纠错是必不可少的（9，10）。然而，并行量子门的实现由于潜在的串扰而变得复杂，特别是在由共模总线完全连接的量子位之间，例如在库仑耦合的捕获原子离子（11，12）或腔耦合的超导transmons（13）中。在这里，我们提出了在一个完全连接的Yb-171（+）离子量子比特阵列中的并行两量子比特纠缠门的实验结果。我们使用深度为4的量子电路（4，14，15）在量子计算机上执行一位全加法运算，其中电路深度表示所需的运行时步骤数。我们的方法利用经典控制技术来利用高度连接的量子比特系统的能力，将有助于加快量子电路的速度，并在捕获离子量子计算机中实现容错。
The circuit model of a quantum computer consists of sequences of gate operations between quantum bits (qubits), drawn from a universal family of discrete operations(1). The ability to execute parallel entangling quantum gates offers efficiency gains in numerous quantum circuits(2-4), as well as for entire algorithms-such as Shor's factoring algorithm(5)-and quantum simulations(6,7). In circuits such as full adders and multiple-control Toffoli gates, parallelism can provide an exponential improvement in overall execution time through the divide-and-conquer technique(8). More importantly, quantum gate parallelism is essential for fault-tolerant error correction of qubits that suffer from idle errors(9,10). However, the implementation of parallel quantum gates is complicated by potential crosstalk, especially between qubits that are fully connected by a common-mode bus, such as in Coulomb-coupled trapped atomic ions(11,12) or cavity-coupled superconducting transmons(13). Here we present experimental results for parallel two-qubit entangling gates in an array of fully connected trapped Yb-171(+) ion qubits. We perform a one-bit full-addition operation on a quantum computer using a depth-four quantum circuit(4,14,15), where circuit depth denotes the number of runtime steps required. Our method exploits the power of highly connected qubit systems using classical control techniques and will help to speed up quantum circuits and achieve fault tolerance in trapped-ion quantum computers.