Photon 'afterglow' could transmit information without transmitting energy

(Phys.org)--Physicists have theoretically shown that it is possible to transmit information from one location to another without transmitting energy. Instead of using real photons, which always carry energy, the technique uses a small, newly predicted quantum afterglow of virtual photons that do not need to carry energy. Although no energy is transmitted, the receiver must provide the energy needed to detect the incoming signal--similar to the way that an individual must pay to receive a collect...