SquareAmplitude
SquareAmplitude[m1, m2]
multiplies the amplitudes from the list m1
with their complex conjugate from the list m2
to obtain the list of products m1im2j. This function can be useful when exporting amplitudes obtained with FeynCalc to FORM.
See also
Overview
Examples
Clear[a1, a2, a3, b1, b2, b3]
SquareAmplitude[{a1, a2, a3}, {b1, b2, b3}]
{a1b1,a1b2,a1b3,a2b1,a2b2,a2b3,a3b1,a3b2,a3b3}
SquareAmplitude[{a1, a2, a3}, {b1, b2, b3}, List -> False]
a1b1+a1b2+a1b3+a2b1+a2b2+a2b3+a3b1+a3b2+a3b3
When the option Real
is set to True
, the amplitudes are assumed to have no imaginary part
SquareAmplitude[{a1, a2, a3}, {b1, b2, b3}, Real -> True, List -> False]
a1b1+2a2b1+a2b2+2a3b1+2a3b2+a3b3
The option Indexed
allows us to attach a marker to each contribution
SquareAmplitude[{a1, a2, a3}, {b1, b2, b3}, Real -> True, List -> False, Indexed -> mark]
a1b1mark(1,1)+2a2b1mark(2,1)+a2b2mark(2,2)+2a3b1mark(3,1)+2a3b2mark(3,2)+a3b3mark(3,3)