Optimized Telecloning Circuits: Theory and Practice of Nine NISQ Clones

Abstract: Although perfect copying of an unknown quantum state is not possible, approximate cloning is possible in quantum mechanics. Quantum telecloning is a variant of approximate quantum cloning which uses quantum teleportation to allow for the use of classical communication to create physically separate clones of a quantum state. We present results of a of $1 \rightarrow 9$ universal, symmetric, optimal quantum telecloning implementation on a cloud accessible quantum computer - the Quantinuum H1-1 device. The H1-1 device allows direct creation of the telecloning protocol due to real time classical if-statements that are conditional on the mid-circuit measurement outcome of a Bell measurement. In this implementation, we also provide an improvement over previous work for the circuit model description of quantum telecloning, which reduces the required gate depth and gate count for an all-to-all connectivity. The demonstration of creating $9$ approximate clones on a quantum processor is the largest number of clones that has been generated, telecloning or otherwise.