Velben

Velben is a fictional unit of measure used in speculative discussions of quantum information and distributed computing. It is defined as a dimensionless quantity that expresses the efficiency of information transfer in a network that uses quantum channels and pre-shared entanglement. In this context, a higher velben indicates more reliable transfer per entanglement resource under a given error tolerance. The concept is used mainly in thought experiments and sci-fi scenarios to compare communication strategies, rather than as a standard in real-world physics. Velben values are reported per channel use and can depend on factors such as channel noise, error-correcting codes, and the amount of shared entanglement.

The term is not part of formal physics or engineering practice and has no universal consensus in the literature. It originated in informal discussions and later appeared in some science fiction writing as a compact way to discuss information-transfer efficiency, sometimes as a narrative device to describe advanced networks.

In practice, when a velben is assigned to protocols, researchers typically specify the assumptions: type of quantum channel, error model, and entanglement rate. Velben can be contrasted with classical metrics like channel capacity or quantum capacity, though it is not a standard metric. See also information theory, quantum communication, entanglement-assisted communication.