What math is used in the theory of quantum computing?

Question

I'd like to know what rung of the math ladder one need be on to grasp how a quantum computer computes.

I realize this might not be a simple answer, so I'm just looking for an idea of the broad topics required.

Thanks.

Answer 1

For the foundation you need to understand linear algebra, projective geometry and how to build circuits out of AND, OR, NOT gates. For the algorithms themselves, you need to know a little about rational approximations and the Fourier transformation. You can start to learn about Quantum Computing from here but I also recommend working through the book he wrote.

Answer 2

Since all quantum algorithms I know, deal with finite dimensional system, knowledge of unitary groups $\text{U}(N)$ is important, because it governs the evolution of the finite quantum system without relaxation. For the QA to approximate the Jones Polynomial, it doesn't hurt to know something about knot theory.