Week 157: Density Matrices

Learning Objectives

• •Construct density matrices for pure and mixed states from physical descriptions
• •Verify all three defining properties (Hermiticity, trace, positivity)
• •Convert between density matrix and Bloch vector representations
• •Calculate purity and von Neumann entropy
• •Compute trace distance and fidelity between states
• •Perform partial trace calculations for two-qubit systems
• •Explain the physical meaning of density matrices in oral exam format