Dense Coding in Experimental Quantum Communication

Abstract

Classically, sending more than one bit of information requires manipulation of more than one two-state particle. We demonstrate experimentally that one can transmit one of three messages, i.e., 1 ``trit'' $\ensuremath{\approx}1.58\mathrm{bit}$, by manipulating only one of two entangled particles. The increased channel capacity is proven by transmitting ASCII characters in five trits instead of the usual 8 bits.