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density matrix
This term is a specialized technical expression used exclusively within quantum mechanics and quantum information theory. It serves as a more general tool than the state vector, allowing physicists to describe systems where there is uncertainty about the exact state, known as mixed states.
In a mathematical context, it is treated as a positive semi-definite operator with a trace of one. Because it is a compound noun referring to a specific mathematical object, it is typically used in a countable sense when referring to different matrices for different systems, though the concept itself is an abstract theoretical framework.
Ý nghĩa
A mathematical operator used in quantum mechanics to describe the statistical state of a quantum system, particularly when the system is in a mixed state rather than a pure state.
The density matrix provides a complete description of the quantum state, including both quantum coherence and classical probabilities.