Teleporting two-qubit entanglement across 19 qubits on a superconducting quantum computer

Abstract

Quantum teleportation is not merely a fascinating corollary of quantum entanglement, it also finds utility in quantum processing and circuit compilation. In this paper, we measure and track the entanglement and fidelity of two-qubit states prepared on a 127-qubit IBM Quantum computer, as one of the qubits is teleported across 19 qubits. We design, evaluate, and compare two distinct approaches to teleportation: postselected measurement categorization and dynamic circuit corrections based on midcircuit measurements, and compare with direct-state transportation using swap gates. By optimally choosing the teleportation path, which exhibits the highest total negativity entanglement measure across nearest-neighbor pairs, we show the entanglement of a two-qubit graph state is sustained after at least 19 hops in teleportation using the postselection approach and 17 hops using the dynamic circuit approach. We observe a higher level of teleported entanglement in paths determined from two-qubit negativities compared to those obtained from gate errors, demonstrating an advantage in using the negativity map over the gate error map for compiling quantum circuits.

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