论文标题
高质量物理Qubits的无选择后准备
Post-selection-free preparation of high-quality physical qubits
论文作者
论文摘要
相干操作的快速改善栅极保真度意味着状态制备和测量中的错误（SPAM）可能成为量子计算机易于断层操作的主要误差来源。这在超导系统中尤其敏锐，在该系统中，测量保真度和量子寿命的折衷情况的总体表现有限。幸运的是，制备和测量的本质上是古典的性质，可以使用辅助码头与经典的控制和选择后提高质量，从而提高质量。然而，实际上，序列后会极大地使综合征提取等过程的调度变得复杂。在这里，我们提出了一个量子电路家族，它们在没有选择后准备高质量| 0>状态，而不是使用cnot和toffoli大门来非线性地计算基础。当两个Quibent Gate Fidelities错误低于0.2％时，我们发现有意义的性能提高，并且当有天然的Toffoli门可用时，性能甚至更好。
Rapidly improving gate fidelities for coherent operations mean that errors in state preparation and measurement (SPAM) may become a dominant source of error for fault-tolerant operation of quantum computers. This is particularly acute in superconducting systems, where tradeoffs in measurement fidelity and qubit lifetimes have limited overall performance. Fortunately, the essentially classical nature of preparation and measurement enables a wide variety of techniques for improving quality using auxiliary qubits combined with classical control and post-selection. In practice, however, post-selection greatly complicates the scheduling of processes such as syndrome extraction. Here we present a family of quantum circuits that prepare high-quality |0> states without post-selection, instead using CNOT and Toffoli gates to non-linearly permute the computational basis. We find meaningful performance enhancements when two-qubit gate fidelities errors go below 0.2%, and even better performance when native Toffoli gates are available.
