## What is quantum information theory?Patrick Hayden ## AbstractQuantum information theory is the generalization of Shannon’s information theory to the realm of quantum mechanics. The basic questions are the same as for standard information theory: What is uncertainty? What is the best method for sending information through a noisy channel? The theory, however, is full of surprises. Random variables don’t commute. Correlation of the quantum variety increases channel capacities. Conditional entropy can be negative. Secrecy can be certified. I’ll give a brief introduction to quantum information theory, highlighting some of the key similarities and striking differences with Shannon theory. |