# Cloning orthogonal quantum states - circuit?

1. Nov 30, 2015

### Emil_M

1. The problem statement, all variables and given/known data
Hey, the no-cloning theorem states, that arbitrary quantum states cannot be cloned by any circuit.

It is, however, possible to clone orthogonal states.

What would a circuit performing this action look like?

2. Relevant equations

Relevant equations: I am assuming you all now the most important quantum gates (CNOT, Hadamard, Pauli Matrices etc. )

3. The attempt at a solution
The circuit looks like this:
$|\psi\rangle$ is a general qubit: $|\psi\rangle := a |0\rangle + b|1\rangle$

I am assuming a CNOT gate has to be applied at some point, followed by the application of further gates to the lower qubit. I am, however, not sure how the coefficients can be "transferred" to the lower qubit.

Thank you!

Last edited: Nov 30, 2015
2. Dec 2, 2015

### Staff: Mentor

What state do you get after the application of the CNOT gate?