Quantum information can not be perfectly cloned, but approximate copies of quantum information can be generated. Quantum telecloning combines approximate quantum cloning, more typically referred as quantum cloning, and quantum teleportation. Quantum telecloning allows approximate copies of quantum information to be constructed by separate parties, using the classical results of a Bell measurement made on a prepared quantum telecloning state. Quantum telecloning can be implemented as a circuit on quantum computers using a classical co-processor to compute classical feed forward instructions using if statements based on the results of a mid-circuit Bell measurement in real time. We present universal, symmetric, optimal $1 \rightarrow M$ telecloning circuits, and experimentally demonstrate these quantum telecloning circuits for $M=2$ up to $M=10$, natively executed with real time classical control systems on IBM Quantum superconducting processors, known as dynamic circuits. We perform the cloning procedure on many different message states across the Bloch sphere, on $7$ IBM Quantum processors, optionally using the error suppression technique X-X sequence digital dynamical decoupling. Two circuit optimizations are utilized, one which removes ancilla qubits for $M=2, 3$, and one which reduces the total number of gates in the circuit but still uses ancilla qubits. Parallel single qubit tomography with MLE density matrix reconstruction is used in order to compute the mixed state density matrices of the clone qubits, and clone quality is measured using quantum fidelity. These results present one of the largest and most comprehensive NISQ computer experimental analyses on (single qubit) quantum telecloning to date. The clone fidelity sharply decreases to $0.5$ for $M > 5$, but for $M=2$ we are able to achieve a mean clone fidelity of up to $0.79$ using dynamical decoupling.

翻译：量子信息不能被完美复制，但可以生成其近似副本。量子远程克隆结合了近似量子克隆（通常简称为量子克隆）与量子隐形传态。通过利用对制备的量子远程克隆态进行贝尔测量所得的经典结果，量子远程克隆允许多个独立方构造量子信息的近似副本。该技术可在量子计算机上通过电路实现，使用经典协处理器实时处理中间电路贝尔测量的结果，并基于条件语句生成前馈指令。我们提出了通用、对称且最优的$1 \rightarrow M$远程克隆电路，并在IBM量子超导处理器（即动态电路）上，通过实时经典控制系统，实验演示了从$M=2$到$M=10$的这些量子远程克隆电路。我们在7台IBM量子处理器上，对布洛赫球面多个不同的消息态执行克隆过程，并可选地使用X-X序列数字动态去耦误差抑制技术。采用两种电路优化方法：一种针对$M=2,3$移除辅助量子比特，另一种在仍使用辅助量子比特的情况下减少电路中的总门数。通过并行单量子比特层析成像与最大似然估计密度矩阵重建，计算克隆量子比特的混合态密度矩阵，并使用量子保真度评估克隆质量。这些结果呈现了迄今为止最大规模、最全面的（单量子比特）量子远程克隆NISQ计算机实验分析之一。当$M>5$时，克隆保真度急剧下降至0.5，但对于$M=2$，我们通过使用动态去耦实现了高达0.79的平均克隆保真度。