One way to build a qubit (e.g. a quantum bit, used for quantum computing) is to isolate a single spin-1/2 particle. In this question, you will think about how you might build and manipulate this qubit. You have at your disposal the qubit itself, and a powerful magnet that can apply static magnetic fields in the z direction, and also time-dependent AC fields of the form (t) = B1 (cos(t)x + sin(t)y) .
Finally, you have a powerful refrigerator, that can cool your system down so that it is in its lowestenergy state.

Your first task is to prepare your qubit in the state | (usually called |0 in the quantum computing literature). Describe a way that you can do this, using your refrigerator and your magnet.