Quantum-Physical Theory of Communication

Claude Shannon's landmark 1948 paper on the mathematical theory of communication shattered conventional wisdom by showing that noisy channels could be used to send data reliably at practical rates, and even went further, showing exactly how to calculate what those rates are. His legacy ranges from the recent Huygens probe photos of Titan to modern cellular phone infrastructure. Despite its phenomenal success, however, Shannon's theory failed to address an extremely important feature of the physical reality: it is quantum mechanical. Over the past decade, researchers have developed a theory of the basic resources useful for communicating in a quantum mechanical world. Shannon's bits are supplemented by ebits of entanglement and qubits of quantum communication, simple data transmission by exotic sounding primitives like teleportation and superdense coding.

The new hybrid theory is full of surprising insights governing what is and is not possible in our quantum mechanical world. I'll try to give a tour of some of these developments, starting with some basic Shannon theory before moving on to quantum information theory and why it is new, interesting, and definitely different.