Part-III Cambridge physics course Lecturer: [Professor Crispin Barnes](https://www.phy.cam.ac.uk/profile/prof-crispin-barnes/) Syllabus: Introduction: The postulates of quantum mechanics - the Copenhagen Interpretation. Quantum entanglement. Density matrices. Measurement 1: What constitutes a measurement? Schrödinger’s cat and Wigner’s friend. The Einstein-Podolsky-Rosen paradox. Some alternative interpretations of quantum mechanics: Many worlds. Bohm’s guiding waves. Transaction interpretation. Histories. Quantum-state diffusion. Hidden variables theories: Bell’s theorem; experimental tests. Quantum Entanglement: Bipartite systems: Schmidt decomposition, reduced density matrix, entanglement measures. Tripartite systems. Measurement 2: Positive Operator Value Measure (POVM); Weak measurements. Decoherence: Decoherence time. Quantum cryptography: The BB84 protocol. The no-cloning theorem. Eavesdropping strategies. Privacy amplification. Other protocols. Experimental realisations. Quantum teleportation: Theoretical strategy and experimental realisations. Quantum computing: Qubits. Logical operations. Algorithms for quantum computers: factorisation, database searches. Error correction. Possible systems for implementing quantum computing: ion traps; nuclear magnetic resonance; semiconductor quantum dots. 