In physics, a heterotic string is a peculiar mixture (or hybrid) of the bosonic string and the superstring (the adjective heterotic comes from the Greek word heterosis, hybrid vigour). In string theory, the left-moving and the right-moving excitations almost do not talk to each other, and it is possible to construct a string theory whose left-moving (counter-clockwise) excitations “think” that they live on a bosonic string propagating in D = 26 dimensions, while the right-moving (clock-wise) excitations “think” that they belong to a superstring in D = 10 dimensions.

Every heterotic string must be a closed string, not an open string; it is not possible to define any boundary conditions that would relate the left-moving and the right-moving excitations because they have a different character.

— Wikipedia on Heterotic string

2011.01.18 Tuesday ACHK