How does a quantum computer fundamentally differ from all the other computer architectures discussed in this book? What allows a quantum computer to achieve the effect of a massively parallel...

How does a quantum computer fundamentally differ from all the other computer architectures discussed in this book? What allows a quantum computer to achieve the effect of a massively parallel computation using a single piece of hardware? How is a supervised ANN programmed to carry out a particular task? What is the difference between a supervised versus unsupervised ANN?