Spontaneous breaking of a metastable string

We consider the phase transition of a string with tension ${\epsilon }_1$ to a string with a smaller tension ${\epsilon }_2$. The transition proceeds through quantum tunneling, and we calculate in arbitrary number of dimensions the preexponential factor multiplying the leading semiclassical exponential expression for the rate of the process. At ${\epsilon }_2=0$ the found formula for the decay rate also describes a breakup of a metastable string into two pieces.

Figure 1

The bounce configuration, describing the semiclassical tunneling trajectory.

Figure 2

Fluctuations around the bounce configuration.

Figure 3

The configuration for the calculation of the renormalization of $\mu$.