von Neumann entropy English

Meaning von Neumann entropy meaning

What does von Neumann entropy mean?

von Neumann entropy noun

— (quantum physics) The entropy of a quantum state. If the state is expressed as a quantum density matrix \rho, then this entropy can be expressed mathematically as S = -\text{tr}(\rho \log \rho) where \text{tr} is the trace operator and the logarithm is natural.