2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/84451It is widely believed that one signal can carry maximum one bit of information, and minimum KTlog2 energy is required to transmit or to erase a bit. Here it is shown four bits of information can be transmitted by one signal in four dimensional space-time. It implies space-time cannot be ignored to determine the minimal energy cost of information processing.Latex, 7 pagesGeneral Physicstext