Entanglement teleportation along a regenerating hamster-wheel graph state

TL;DR

This paper demonstrates a cyclic quantum teleportation protocol on a 20-qubit ion-trap processor, preserving entanglement over multiple revolutions around a ring, advancing measurement-based quantum computation.

Contribution

It introduces an efficient, reusable teleportation scheme along a regenerating graph state on a real quantum device, enabling entanglement preservation over multiple cycles.

Findings

58% entanglement retention after three revolutions on real hardware

Teleportation fidelity remains high after 56 qubits hops

45% entanglement retention after 100 hops on noisy emulator

Abstract

We scheme an efficient and reusable approach to quantum teleportation that allows cyclic teleportation of a two-qubit graph state around a quantum hamster wheel -- a ring of qubits entangled as a one-dimensional line prepared on the 20-qubit Quantinuum H1-1 ion-trap quantum processor. The qubits on the ring are periodically measured and reused to achieve a teleportation depth that exceeds the total number of available qubits in the quantum processor. Using the outcomes measured during teleportation, we calculate and apply byproduct operators through dynamic circuits to correct local transformations induced on the teleported state. We evaluate the quality of teleportation by tracing the preserved entanglement and fidelity of the teleported two-qubit graph state from its density matrix. In the real-machine experiments, we demonstrate that 58% of the teleported state's entanglement is sustained with a measured two-qubit negativity of $0.291\pm0.018$ after three complete revolutions around the hamster wheel, or equivalently, after hopping across 56 qubits. On the machine-specific noisy emulator, we found that the teleported state after 100 hops still sustained 45% of its entanglement. By performing teleportation along a regenerating graph state, our work is a step forward in demonstrating the feasibility of measurement-based quantum computation.