Parity (physics)
![Two dimensional representations of parity are given by a pair of quantum states which go into each other under parity. However, this representation can always be reduced to linear combinations of states, each of which is either even or odd under parity. One says that all irreducible representations of parity are one-dimensional.](/Images/godic/202502/01/Parity_1drep3503.png")
![Top: P-symmetry: A clock built like its mirrored image will behave like the mirrored image of the original clock.Bottom: P-asymmetry: A clock built like its mirrored image will not behave like the mirrored image of the original clock.](/Images/godic/202502/01/Parity_clocks_-_P-conservation.svg3503.png")
![](/Images/godic/202502/01/Parity_clocks_-_P-violation.svg3503.png")
In quantum mechanics, a parity transformation (also called parity inversion) is the flip in the sign of one spatial coordinate. In three dimensions, it is also often described by the simultaneous flip in the sign of all three spatial coordinates (a point reflection):