Bell state

A Bell state is one of four standard joint states of two qubits that are as entangled as two qubits can be, so their amplitudes will not split into a line for each wire. The version prepared on this site has equal amplitudes on 00 and 11, with the same sign. It is named for John Bell, whose 1964 paper showed that its correlations, measured along several directions, cannot be copied by answers fixed in advance on each wire if neither wire can influence the other.

Keith hears the name and asks whether a word could be pushed from one wire to the other. Malcolm keeps the name on the joint amplitudes, and on the fact that each wire of this version, looked at by itself, is still a fair toss.