Quantum networks are systems that connect different users or devices using principles of quantum mechanics. In the future, these networks could help improve the security of communications.

For entanglement-based quantum networks to work, however, researchers need to be able to verify that particles are entangled and assess the extent of their entanglement. Entanglement is a quantum mechanical effect in which the shared states of distant particles cannot be described as separate or independent.

Researchers at Shandong University recently introduced a new approach for verifying entanglement in a quantum network that does not require trusting the equipment used to analyze and detect photons (i.e., light particles), as most previously developed strategies do.