- #1

RJLiberator

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## Homework Statement

We know: In a measurement of quantum mechanics (basic) the average value is the cosine of the angle between the orthonormal basis of the measurement apparatus and the qubit (vector) entering it.

**Question**: How do we prove this?

## Homework Equations

## The Attempt at a Solution

Can there be a mathematical proof to this? Or is this done by painstaking experiments in a laboratory?

If you can answer this question, then I will know how to proceed.

Thank you.