Reconnection of non-abelian cosmic strings

Abstract

Cosmic strings in non-abelian gauge theories naturally gain a spectrum of massless, or light, excitations arising from their embedding in color and flavor space. This opens up the possibility that colliding strings miss each other in the internal space, reducing the probability of reconnection. We study the topology of the non-abelian vortex moduli space to determine the outcome of string collision. Surprisingly we find that the probability of classical reconnection in this system remains unity, with strings passing through each other only for finely tuned initial conditions. We proceed to show how this conclusion can be changed by symmetry breaking effects, or by quantum effects associated to fermionic zero modes, and present examples where the probability of reconnection in a U(N) gauge theory ranges from 1/N for low-energy collisions to one at higher energies.

Non-Abelian vortices on a cylinder: Duality between vortices and walls

“…The movable position of the small kink in I = −1 is bounded from both sides like the single vortex case, resulting in a CP 1 factor again. However the size of this CP 1 is twice of that of the single vortex as was found in [23]. 8 In our configuration this phenomenon can be explained as follows.…”

“…16-(a)) just as in the single vortex case, giving two CP 1 factors. Therefore as found in [23,24] asymptotic behavior of the moduli space of well separated vortices is found to be…”

Non-Abelian vortices in SO(N) and USp(N) gauge theories

“…In fact, by physical arguments, we always expect the following relation among the dimensions of the moduli spaces: 13) which is valid both for the local and semi-local case. This relations can be readily used to generalize the above equations to the other cases, including special points with odd chirality.…”

“…(3.8). 13 Next we link the lattice points painted with the same color, namely the patches related by the permutation P r with det P r = +1. The structure of the moduli space discussed above can easily be read off from the dual weight diagram obtained this way.…”

“…[9]- [12] in order to exhaust all possible moduli. The moduli and transformation properties of the moduli in the cases of composite vortices (higherwinding vortices) [13][14][15][16] and semi-local vortices [17,18], have been studied. A new type of (Seiberg-like) duality was found among pairs of models having related vortex moduli, sharing a common sigma-model-lump limit [18].…”