Patent ID: 7126691

Claim:
Communications apparatus comprising: A) means for generating pairs of particles that are quantum mechanically entangled with respect to a quantum state variable, said particle pairs being arranged as a first beam of particles and a second beam of particles, where every particle in said first beam of particles has its quantum entangled counterpart in said second beam of particles (and vice versa), B) a receiver comprising 1) means for separating the particles in said first beam of particles into a third beam of particles and a fourth beam of particles according to the value of said quantum mechanical state variable, 2) means for recombining said third and fourth beam of particles in such a manner as to generate quantum interference, and 3) means for detecting the presence or absence of quantum interference in said recombining means, and C) a transmitter comprising 1) means for separating the particles in said second beam of particles that is capable of separating the particles either according to the value of said quantum state variable or according to the value of the quantum state variable that is orthogonal to said quantum state variable, the mode of separation being selectable at the time when the invention is in operation, 2) means for selecting said mode of separation of said separating means, and 3) means for absorbing the particles emitted by said separating means.