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topic:qm:density-matrix
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| topic:qm:density-matrix [2023/02/15 18:54] – [Postulates in Density operator form] samuel | topic:qm:density-matrix [2023/02/15 18:56] (current) – samuel | ||
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| **4.** | **4.** | ||
| + | ===== Properties ===== | ||
| + | * $\tr(\rho^2) <= 1$ | ||
| + | * $\rho$ is a pure state if and only if $\tr(\rho^2) == 1$. | ||
| ===== Linking state vector and density matrix ===== | ===== Linking state vector and density matrix ===== | ||
| For multiple pure states it is defined as $$ \rho = \sum_i p_i{\ket{\psi_i}\bra{\psi_i}} $$. | For multiple pure states it is defined as $$ \rho = \sum_i p_i{\ket{\psi_i}\bra{\psi_i}} $$. | ||
topic/qm/density-matrix.1676487270.txt.gz · Last modified: by samuel
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