Entropy and asymptotics / Definition

Von Neumann entropy definition

Definition statement

For a quantum state $\rho_A$ on a finite-dimensional system $A$, its von Neumann entropy is defined as $H(A)_\rho := -\operatorname{Tr}\!\bigl(\rho_A \log_2 \rho_A\bigr).$ Equivalently, it is the Shannon entropy of the eigenvalues of $\rho_A$.

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