论文标题
无需嵌入在Qudit空间中的量子位的通用测量值
Ancilla-free implementation of generalized measurements for qubits embedded in a qudit space
论文作者
论文摘要
信息完整（IC）正（）正算子值衡量标准（POVM）是广义量子测量值，比标准计算基础读数具有优势。例如，IC-POVM可以有效提取操作员期望值，这是许多量子算法中的关键步骤。 POVM测量通常是通过将一个附加的Ancilla量子耦合到每个逻辑量子的实现，从而对设备尺寸和连接施加了很高的需求。在这里，我们展示了如何在没有Ancilla Qubits的情况下实现一般类IC-POVM。我们利用Qudit的高维希尔伯特空间，其中经常被编码。然后，可以通过将每个量子耦合到两个可用的Qudit状态，然后进行投影测量，从而实现POVM。我们开发了所需的控制脉冲序列，并通过脉冲级模拟来数字建立了它们用于超导transmon速度的可行性。最后，我们介绍了IBM量子硬件上的Qudit空间POVM测量值的实验证明。这为使POVM测量广泛用于量子计算应用程序铺平了道路。
Informationally complete (IC) positive operator-valued measures (POVMs) are generalized quantum measurements that offer advantages over the standard computational basis readout of qubits. For instance, IC-POVMs enable efficient extraction of operator expectation values, a crucial step in many quantum algorithms. POVM measurements are typically implemented by coupling one additional ancilla qubit to each logical qubit, thus imposing high demands on the device size and connectivity. Here, we show how to implement a general class of IC-POVMs without ancilla qubits. We exploit the higher-dimensional Hilbert space of a qudit in which qubits are often encoded. POVMs can then be realized by coupling each qubit to two of the available qudit states, followed by a projective measurement. We develop the required control pulse sequences and numerically establish their feasibility for superconducting transmon qubits through pulse-level simulations. Finally, we present an experimental demonstration of a qudit-space POVM measurement on IBM Quantum hardware. This paves the way to making POVM measurements broadly available to quantum computing applications.
