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A positive trace-one operator representing pure or mixed quantum states and reduced states of subsystems.
wp-physics-density_operatornlab-physics-density_operatortong-quantumEach relation below ends at this concept.
This is an authored directed relation from the source endpoint to the target endpoint.
Mixed states are represented by positive trace-one density operators; pure states are the rank-one case.
The target represents a state, property, observable, or state-dependent description associated with the source system or theory.
wp-physics-density_operatornlab-physics-density_operatorwp-physics-quantum_statenlab-physics-mixed_quantum_stateThis is an authored directed relation from the source endpoint to the target endpoint.
Taking the partial trace of a composite-system density operator canonically constructs the positive trace-one density operator of the retained subsystem.
Apply a standard functorial or canonical construction whose output is not merely a reduct of the input and is not generally an equivalent presentation of the same object.
wp-partial_tracenlab-partial_tracetong-quantumwp-physics-quantum_statenlab-physics-mixed_quantum_stateThis is an authored directed relation from the source endpoint to the target endpoint.
A density operator is a positive operator satisfying the additional normalization and trace-class conditions required for a quantum state.
A more specific theory, model, entity class, or regime is obtained by restricting or extending the scope of a broader framework.
wp-positive_operatornlab-positive_operatortong-quantumwp-physics-density_operatornlab-physics-density_operatorThis is an authored directed relation from the source endpoint to the target endpoint.
A normal density operator is a positive trace-class operator with unit trace; trace class alone is necessary in infinite dimensions but not sufficient.
A more specific theory, model, entity class, or regime is obtained by restricting or extending the scope of a broader framework.
wp-trace_class_operatornlab-trace_class_operatortong-quantumwp-physics-density_operatornlab-physics-density_operatorEach relation below starts at this concept.
This is an authored directed relation from the source endpoint to the target endpoint.
For a density operator , the expectation of an observable is whenever the product and trace are defined.
The target represents a state, property, observable, or state-dependent description associated with the source system or theory.
tong-quantumwp-physics-expectation-valuenlab-physics-expectation-valueThis is an authored directed relation from the source endpoint to the target endpoint.
Density operators represent quantum statistical ensembles and reduced equilibrium states, with expectation values computed by traces. Not every density operator is an equilibrium Gibbs state.
The source supplies a substantive formal ingredient, dynamical sector, law, field content, or mechanism of the target theoretical framework.
wp-physics-density_operatorwp-physics-quantum-statistical-mechanicstong-statistical-physics