Quantum entanglement, by itself, cannot be used to communicate. Measuring the state of one qubit can instantaneously change the state of its entangled partner, no matter how far away, but that change can't convey a message. Entanglement can, however, enhance the security, capacity, or accuracy of a communication channel.
In one example, researchers led by William Matthews (University of Waterloo, Canada) and Andreas Winter (University of Bristol, UK) showed last year that when two communicating parties—Alice and Bob—share pairs of entangled qubits, they can transmit more classical information in a single use of a communication channel than they otherwise could.1 Matthews and Winter's work was theoretical. Now, Robert Prevedel, Kevin Resch, Matthews, and other Waterloo colleagues have implemented a similar protocol experimentally.2 Without shared entanglement, a single use of their channel can transmit a single bit with a success rate of 83.3%. With shared entanglement, the researchers achieved...