An international group of researchers from the University of Turku under the direction of Guangcan Guo from the University of Science and Technology of China of the Chinese Academy of Sciences successfully overcame environmental noise to achieve high-fidelity quantum teleportation by utilizing multipartite hybrid entanglement, which will help in understanding quantum nonlocality. This study was published in the journal Science Advances.
Stages of noisy quantum teleportation. Image Credit: Zhao-Di Liu et al.
A key protocol in quantum communication is quantum teleportation, which uses quantum entanglement to transmit unknown quantum states over long distances. However, noise greatly affects quantum teleportation because quantum entanglement is so brittle. One major problem has been to achieve high-fidelity quantum teleportation in noisy situations.
Previously, the research team used programmable spatial light modulators and smart optical route design to provide a comprehensive strategy for controlling photon polarization and frequency to address the decoherence issue of open quantum systems in a noisy environment. Using nonlocal memory effects, they achieved quantum teleportation that transcends noise and developed a completely programmable phase decoherence quantum simulator.
Nonlocal memory effects, however, necessitate demanding quantum resources, including environmental entanglement, which are typically unachievable. Expanding upon these findings, the present study introduces a more flexible quantum teleportation method that successfully reduces ambient noise.
The researchers prepared a dual-photon polarization-frequency hybrid entangled starting state by introducing particular phase modulations into the environment using the completely adjustable phase decoherence quantum simulator. These photons were then sent to two different user terminals, where they underwent evolutions of decoherence.
In the end, the scientists used unitary operations appropriate for the recovered quantum bits in classical communication to reconstruct the transmitted quantum state, with a measured fidelity of about 90 %.
Bell's inequality was never violated by the polarization states, suggesting concealed quantum nonlocality-based quantum teleportation. Unlike traditional methods like dynamic decoupling and decoherence-free subspaces, this approach provides a novel way to eliminate ambient noise and advances the understanding of quantum nonlocality.
Journal reference:
Liu, Z.-D., et al. (2024) Overcoming noise in quantum teleportation with multipartite hybrid entanglement. Science Advances. doi.org/10.1126/sciadv.adj3435