  Quantum dense coding has been demonstrated experimentally in terms of quantum
logic gates and circuits in quantum computation and NMR technique. Two bits of
information have been transmitted through manipulating one of the maximally
entangled two-state quantum pair, which is completely consistent with the
original ideal of Bennett-Wiesner proposal. Although information transmission
happens between spins over inter-atomic distance, the scheme of entanglement
transformation and measurement can be used in other processes of quantum
information and quantum computing.
