Mobile impurity in the Kitaev chain: Phase diagram and signatures of topology
Phys. Rev. B 113, 155146 – Published 21 April, 2026
DOI: https://doi.org/10.1103/r9zk-5wny
Abstract
We study the physics of a mobile impurity immersed in a one-dimensional topological superconductor. We discuss the phase diagram of this system obtained with exact diagonalization and Chevy-type variational Ansatz. We argue that the character of the transition from a weak to strong coupling regime depends on the phase of the host superconductor. A smooth crossover between a weakly coupled polaron and a molecular state is observed in the topological phase. In contrast, the impurity undergoes a sharp polaron-molecule transition in a topologically trivial background.
