Researchers at Oak Ridge National Laboratory 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.
Using a technology developed at ORNL known as a quantum frequency processor, the researchers demonstrated widely applicable quantum gates, or the logical operations necessary for performing quantum communications protocols. In these protocols, researchers need to be able to manipulate photons in a user-defined way, often in response to measurements performed on particles elsewhere in the network.
With the Bell state analyzer completed, Lukens and colleagues are looking to expand to a complete entanglement swapping experiment, which would be the first of its kind in frequency encoding. (Phys.org)
Their results have been published in Optica.