Researchers at the Department of Energy’s Oak Ridge National Laboratory, SRI International, Freedom Photonics and Purdue University have made strides toward a fully quantum internet by designing and demonstrating the first-ever Bell state analyzer for frequency bin coding.
Entanglement between two qubits is considered maximized when the qubits are said to be in “Bell states.”
Measuring these Bell states is critical to performing many of the protocols necessary to perform quantum communication and distribute entanglement across a quantum network. And while these measurements have been done for many years, the team’s method represents the first Bell state analyzer developed specifically for frequency bin coding, a quantum communications method that harnesses single photons residing in two different frequencies simultaneously.
The analyzer was designed with simulations and has demonstrated 98% fidelity; the remaining 2% error rate is the result of unavoidable noise from the random preparation of the test photons, and not the analyzer itself. This incredible accuracy enables the fundamental communication protocols necessary for frequency bins. (SciTechDaily)
Their findings were published in Optica.
