And so, the thing that you often have to respond to is this idea that a quantum computer can be zero and can have all these qubits that are zero and one simultaneously, and therefore they can solve really complex problems by looking at every possible combination of those all at once, and that’s not true. So explain why that isn’t true or what is true, how ever you want to do it.
This article consists of a very short introduction to classical and quantum information theory. Basic properties of the classical Shannon entropy and the quantum von Neumann entropy are described, along with related concepts such as classical and quantum relative entropy, conditional entropy, and mutual information. A few more detailed topics are considered in the quantum case.
An Introduction to Quantum Computation and Quantum Communication. Rob Pike, Bell Labs
Das neue Signaturverfahren namens XMSS soll auch der Rechenpower von Quantencomputern standhalten.