A research team led by Academician GUO Guangcan from the University of Science and Technology of China (USTC) of the Chinese Academy of Sciences (CAS), in collaboration with the research team at the University of Turku, Finland, successfully overcame environmental noise to achieve high-fidelity quantum teleportation by utilizing multipartite hybrid entanglement. Their findings were published in Science Advances on May 1st.
Quantum teleportation serves as a crucial protocol in quantum communication, enabling the remote transmission of unknown quantum states through the utilization of quantum entanglement. However, due to the fragile nature of quantum entanglement, quantum teleportation is highly susceptible to noise. Achieving high-fidelity quantum teleportation in noisy environments has been a pressing challenge.
Previously, to address the decoherence issue of open quantum systems in a noisy environment, the research team devised a comprehensive method for regulating photon polarization and frequency, leveraging sophisticated optical path design and programmable spatial light modulators. This approach enabled them to create a fully controllable phase decoherence quantum simulator and achieve quantum teleportation that surpasses noise, utilizing nonlocal memory effects.
However, nonlocal memory effects require stringent quantum resources such as environmental entanglement, which are not generally attainable. Building on these results, the current work presents a more versatile quantum teleportation technique that effectively mitigates environmental noise.
Employing the fully controllable phase decoherence quantum simulator, the researchers introduced specific phase modulations into the environment to prepare a dual-photon polarization-frequency hybrid entangled initial state. Subsequently, these photons were distributed to two separate user terminals, where each underwent decoherence evolution.
Ultimately, through classical communication, the researchers executed suitable unitary operations on the retrieved quantum bits to restore the transmitted quantum state, achieving a measured fidelity approaching 90%. The polarization states never violated Bell's inequality, indicating quantum teleportation based on hidden quantum nonlocality. This method offers a new way to overcome environmental noise, distinct from conventional techniques such as dynamic decoupling and decoherence-free subspaces, and enhances the understanding of quantum nonlocality.
Stages of noisy quantum teleportation. (Image by USTC)
（Written by ZHANG Min, Edited by WU Yuyang, USTC News Center）