Superconductor/Insulator Transition in the Striped Phase

We study the transversal dynamics of a charged stripe (quantum string) at $T = 0$ and show that its kink excitations play the role of current carriers. If the hopping amplitude $t$ is much smaller than the string tension $J$, the string is pinned and its ground state (GS) is insulating. At $t \gg J$, the string is depinned and the GS is a kink-condensate. By mapping the system onto a Josephson junction chain, we show that this state is superconducting. At $(t/J)_c = 2 / \pi^2$ the kink/antikink pairs decouple and a Kosterlitz-Thouless like insulator-superconductor transition occurs.