AtomicDensityMatrix`
AtomicDensityMatrix`

# DensityMatrix

DensityMatrix[sys]

forms the density matrix for an atomic system (list of AtomicState objects) sys.

# Details and Options

• The following options can be given:
•  AllowedElements All density-matrix elements that are allowed to be nonzero ComplexExpandVariables False whether to express density-matrix elements in terms of real and imaginary parts DMLabel None additional label for density-matrix elements DMSymbol ρ symbol to use for density-matrix elements NeglectedElements None density-matrix elements that are required to be zero Representation "Zeeman" Zeeman or polarization-moment representation TimeDependence True whether density-matrix elements should have explicit time dependence TimeVariable t symbol to use for time variable
• Possible values for the Representation option include "Zeeman" and "PolarizationMoments".
• Possible values for the ComplexExpandVariables option are True, False, and Subscript, meaning real and imaginary parts are indicated in a subscript.
• Density-matrix elements are set to zero if they are specified by the NeglectedElements option or if they are not specified by the AllowedElements option.

# Examples

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## Basic Examples(3)

Density matrix for a system with no angular momentum:

Density matrix for a system with Zeeman structure:

Density matrix for a system with hyperfine structure:

## Options(8)

### AllowedElements(1)

Write a density matrix allowing only matrix elements between states with and :

### ComplexExpandVariables(1)

Write density matrix in terms of real and imaginary parts:

Indicate real and imaginary parts using subscript labels:

### DMLabel(1)

Label the density matrix elements:

### DMSymbol(1)

Use a different symbol for the density matrix:

### NeglectedElements(1)

Write a density matrix neglecting the matrix elements between states with and :

### Representation(1)

Write the density matrix in the polarization-moment representation:

### TimeDependence(1)

Remove explicit time dependence:

### TimeVariable(1)

Use a different time variable: