Definition for "Density Matrix" in the Quantum Dictionary

- Modern Physics -

Quantum Mechanics Dictionary

A quantum mechanics concept defining a model element, mathematical object, or experimental method used to predict measurable outcomes. It applies when required assumptions and definitions are specified and yields computable probabilities and expectation values. It does not ensure correctness without validation of approximations, numerical stability, and consistency of units and conventions.

Natural & Formal Sciences Dictionary

An operator (density operator) ρ on a Hilbert space that represents the statistical state of a quantum system, encoding both classical statistical mixtures and quantum coherences; expectation values of observables are given by Tr(ρA).