- #1
tomdodd4598
- 138
- 13
Hey there,
I've suddenly found myself trying to learn about the Lorentz group and its representations, or really the representations of its double-cover. I have now got to the stage where the 'complexified' Lie algebra is being explored, linear combinations of the generators of the rotations and boosts have been defined, and the pairs of eigenvalues (m,n) of these linear combinations label the representations, where m and n are half-integers.
Now, all of this I think is fine (maybe I have some of the details wrong), but I've read something that has confused me a little on the Wikipedia article:
"Since for any irreducible representation for which m ≠ n it is essential to operate over the field of complex numbers, the direct sum of representations (m, n) and (n, m) have particular relevance to physics, since it permits to use linear operators over real numbers."
Could someone explain this in a little more detail? In particular, why do the irreducible representations for which m ≠ n not have relevance to physics, such as the (0, ½) or (½, 0)?
I've suddenly found myself trying to learn about the Lorentz group and its representations, or really the representations of its double-cover. I have now got to the stage where the 'complexified' Lie algebra is being explored, linear combinations of the generators of the rotations and boosts have been defined, and the pairs of eigenvalues (m,n) of these linear combinations label the representations, where m and n are half-integers.
Now, all of this I think is fine (maybe I have some of the details wrong), but I've read something that has confused me a little on the Wikipedia article:
"Since for any irreducible representation for which m ≠ n it is essential to operate over the field of complex numbers, the direct sum of representations (m, n) and (n, m) have particular relevance to physics, since it permits to use linear operators over real numbers."
Could someone explain this in a little more detail? In particular, why do the irreducible representations for which m ≠ n not have relevance to physics, such as the (0, ½) or (½, 0)?