Tensor[ConjugateSpinor] - calculate the complex conjugate of a spinor
Calling Sequences
ConjugateSpinor(S, ConjCoord)
Parameters
S - a spinor
ConjCoord - (optional) keyword argument conjugatecoordinates = C, where C is a list of lists specifying conjugate coordinates
Description
Examples
See Also
The command ConjugateSpinor(S) calculates the complex conjugate of an arbitrary spinor S.
For spinors with real parameters, the assuming command of Maple can be used to properly calculate the complex conjugates.
This command is part of the DifferentialGeometry:-Tensor package, and so can be used in the form ConjugateSpinor(...) only after executing the commands with(DifferentialGeometry); with(Tensor) in that order. It can always be used in the long form DifferentialGeometry:-Tensor:-ConjugateSpinor.
with⁡DifferentialGeometry:with⁡Tensor:
Example 1.
First create a vector bundle E→M with base coordinates x,y,z,t and fiber coordinates z1,z2,w1,w2. For spinor applications, it is tacitly assumed that z1,z2 are complex coordinates with complex conjugates w1,w2.
DGsetup⁡x,y,z,t,z1,z2,w1,w2,E
frame name: E
Define spinors S1 and S2 and calculate their complex conjugates.
S1≔D_z1
S1:=D_z1
ConjugateSpinor⁡S1
D_w1
S2≔dw1+3⁢I⁢dw2
S2:=dw1+3⁢I⁢dw2
ConjugateSpinor⁡S2
dz1−3⁢I⁢dz2
Example 2.
The two type 1,1 Kronecker delta spinors are complex conjugates of each other.
S3≔KroneckerDeltaSpinor⁡spinor
S3:=D_z1⁢dz1+D_z2⁢dz2
S4≔KroneckerDeltaSpinor⁡barspinor
S4:=D_w1⁢dw1+D_w2⁢dw2
ConjugateSpinor⁡S3&minusS4
0⁢D_z1⁢dz1
Example 3.
The soldering form is always a Hermitian spinor. To check this calculate, first define the solder form σ, then conjugate σ and interchange the 2nd and 3rd indices. The result is the original solder form σ.
F≔D_t,D_x,D_y,D_z:
σ≔SolderForm⁡F
σ≔22⁢dx⁢D_z1⁢D_w2+22⁢dx⁢D_z2⁢D_w1−I2⁢2⁢dy⁢D_z1⁢D_w2+I2⁢2⁢dy⁢D_z2⁢D_w1+22⁢dz⁢D_z1⁢D_w1−22⁢dz⁢D_z2⁢D_w2+22⁢dt⁢D_z1⁢D_w1+22⁢dt⁢D_z2⁢D_w2
bar_sigma≔ConjugateSpinor⁡σ
bar_sigma≔22⁢dx⁢D_w1⁢D_z2+22⁢dx⁢D_w2⁢D_z1+I2⁢2⁢dy⁢D_w1⁢D_z2−I2⁢2⁢dy⁢D_w2⁢D_z1+22⁢dz⁢D_w1⁢D_z1−22⁢dz⁢D_w2⁢D_z2+22⁢dt⁢D_w1⁢D_z1+22⁢dt⁢D_w2⁢D_z2
σ&minusRearrangeIndices⁡bar_sigma,2,3
0⁢dx⁢D_z1⁢D_z1
Example 4.
Use the Maple assuming command to simplify the complex conjugate of a spinor-tensor containing a real parameter α.
S5≔evalDG⁡α⁢D_t&tD_w1+xα⁢D_z&tD_w2
S5≔xα⁢D_z⁢D_w2+α⁢D_t⁢D_w1
S6≔ConjugateSpinor⁡S5assumingα::real
S6≔xα⁢D_z⁢D_z2+α⁢D_t⁢D_z1
Example 6.
In some applications complex coordinates on the base space are used. Suppose, for example, that z and t are real coordinates and that u is a complex coordinate with complex conjugate v.
DGsetup⁡u,v,z,t,z1,z2,w1,w2,N
frame name: N
S7≔evalDG⁡v⁢D_z1&tdz2+t⁢u⁢D_z2&tdz1
S7≔v⁢D_z1⁢dz2+t⁢u⁢D_z2⁢dz1
Use the keyword argument conjugatecoordinates to specify that the conjugate of u is v (and the conjugate of v is u).
ConjugateSpinor⁡S7,conjugatecoordinates=u,v
u⁢D_w1⁢dw2+t⁢v⁢D_w2⁢dw1
S8≔evalDG⁡α⁢D_u&tdz2
S8≔α⁢D_u⁢dz2
ConjugateSpinor⁡S8,conjugatecoordinates=u,vassumingα::real
α⁢D_v⁢dw2
DifferentialGeometry, Tensor, assuming, DGmap, KroneckerDeltaSpinor, RearrangeIndices, SolderForm
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