Density operator for pure quantum states

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📚 We have mostly been doing quantum mechanics using state vectors called kets. In this video we introduce the density operator, which provides an alternative but equivalent way of doing quantum mechanics. The obvious question is: why bother? In this video we only look at pure states to have a nice introduction to the ideas behind the density operator. However, to see the full power of the density operator we need to look at systems for which we only have incomplete information that is described by mixed states, such as those that feature in quantum statistical mechanics.

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⏮️ BACKGROUND
Dirac notation in state space:    • Dirac notation: state space and dual ...  
Operators in quantum mechanics:    • Operators in quantum mechanics  
Eigenvalues and eigenstates:    • Eigenvalues and eigenstates in quantu...  
Projection operators:    • Projection operators in quantum mecha...  
Pure and mixed states:    • Pure vs. mixed quantum states  
Measurements | Maths:    • Measurements in quantum mechanics || ...  
Schrödinger equation:    • The Schrödinger equation  

⏭️ WHAT NEXT?
Density operator for mixed states:    • Density operator for mixed quantum st...  

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Director and writer: BM
Producer and designer: MC