GroupTheory`
GroupTheory`

GTCharProjectionOperator

GTCharProjectionOperator[classes,characters,function,arguments]

applies the character projection operator corresponding to an irreducible representation to a certain function with given arguments.

Details and Options

  • The Projection operator is given by , where is the dimension of the irreducible representation with characters and is the order of the group.
  • The characters belong to an irreducible representation of the group . The classes and characters can be obtained using the command GTCharacterTable.
  • arguments is a list of arguments used by function, typically {x,y,z}
  • The following option can be given:
  • GOFast FalseControls the input validation
    GOLattice{{0, 0, 0}, {0, 0, 0}, {0, 0, 0}}Gives the lattice vectors in case space groups are considered
  • See: W. Hergert, M. Geilhufe, Group Theory in Solid State Physics and Photonics. Problem Solving with Mathematica, chapter 5.9

Examples

open allclose all

Basic Examples  (3)

First, load the package:

For the example, the point group is considered. The point group and the character table are generated as follows:

The function will be analysed.

The application of the character projection operator, related to the irreducible representation can be calculated by:

and for the irreducible representation by:

The same formalism holds for the irreducible representation ,

GTCharProjectionOperator can also be used for 3-dimensional vector functions.

If a double group is installed, GTCharProjectionOperator can be used for spinor functions.

Generalizations & Extensions  (1)

The function will be analysed.

If a whole character table is supplied, GTCharProjectionOperator applies the character projection operator for every irreducible representation.

Options  (2)

GOFast  (2)

The function will be analysed.

The evaluation time can be decreased, using GOFastTrue.

If GOFastFalse is used, a check of the input will be performed.