Quantum teleportation with coherent error in Bell-state measurement

TL;DR

This paper analyzes how coherent errors in Bell-state measurements affect quantum teleportation performance and proposes strategies to maintain unit fidelity despite imperfect measurements.

Contribution

It provides an analytical framework linking measurement entanglement to teleportation success and offers methods to overcome limitations of partially entangled measurements.

Findings

Measurement entanglement determines teleportation fidelity.

A quantitative relation between measurement, channel entanglement, and success probability is derived.

Strategies to recover unit fidelity with imperfect entangling operations are proposed.

Abstract

Quantum teleportation is a fundamental protocol in quantum information science, whose performance is conventionally evaluated under the assumption of ideal Bell-state measurements. In realistic implementations, however, joint measurements are often imperfect and can deviate from maximally entangled bases due to coherent errors in entangling operations. In this work, we analytically show how the entanglement of joint measurements determines teleportation performance and propose a strategy to overcome the limitations imposed by partially entangled joint measurements to recover the unit teleportation fidelity. We then derive an exact equation revealing a quantitative relation between measurement entanglement, channel entanglement, and the success probability to realize the unit-fidelity teleportation. We illustrate our results using elegant joint measurements and realistic coherent error models arising from imperfect entangling operations in quantum systems. Our work provides fundamental insight into the role of measurement entanglement in quantum teleportation and establishes a practical framework for achieving faithful teleportation without requiring substantial modifications to existing hardware.