# I Singlet state meaning

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1. Nov 5, 2016

### Silviu

Hello! I am a bit confused about the relation between the singlet configuration and symmetry of the system. So in the spin case, for 2, 1/2 particles, the singlet configuration is antisymmetric. But I read that the quarks are always in a singlet configuration, which means that they are symmetric in the color space. So as I understand, in one case singlet state is associated with symmetry, while in the other with antisymmetry. Is there a rule here?
Thank you!

2. Nov 5, 2016

### Orodruin

Staff Emeritus
Singlet refers to something transforming according to the trivial representation of some symmetry group. It is used in several different applications in physics.

When you put several representations of a group together they generally split into several different irreducible representations, where some may be singlets. Exactly how this occurs depends on the group.

The three-quark color singlet representation is the anti-symmetric product of three fundamental representations.