1. Quantum Fundamentals

Superposition — Quiz

Test your understanding of superposition with 5 practice questions.

Practice Questions

Question 1

Which density matrix corresponds to the pure superposition state $|\psi\rangle=(|0\rangle+|1\rangle)/\sqrt{2}$?

Question 2

Given the qubit state $|\psi\rangle=\cos(\tfrac{\pi}{4})|0\rangle+e^{i\pi/3}\sin(\tfrac{\pi}{4})|1\rangle$, what are its Bloch sphere coordinates $(x,y,z)$?

Question 3

In a two-path interferometer the fringe visibility $V$ and path distinguishability $D$ satisfy $V^2+D^2\le1$. If $V=0.8$, what is the maximum possible value of $D$?

Question 4

In a Mach–Zehnder interferometer with a phase shift $\phi$ in one arm, what is the probability $P_1$ of detection at output port 1?

Question 5

Which statement best illustrates the superposition principle in quantum mechanics?