arXiv:1210.6922 · Physical Review A
Quantum Ising dynamics and Majorana-like edge modes in the Rabi lattice model
Brijesh Kumar, Somenath Jalal
Abstract
The atomic dipoles in the Rabi lattice model exhibit quantum Ising dynamics in the limit of strong atom-photon interaction. It governs the paraelectric to ferroelectric phase transition in the ground state. On an open chain, it implies the existence of two Majorana-like, albeit topologically unprotected, edge modes in the ordered phase. The relation ${\ensuremath{\rho}}_{1L}^{x}={p}^{8}$ between the end-to-end dipole correlation ${\ensuremath{\rho}}_{1L}^{x}$ and the spontaneous polarization $p$ is proposed as an observable signature of these edge modes. The density-matrix renormalization-group calculations on the one-dimensional Rabi lattice support the strong-coupling quantum Ising behavior and correctly yield the proposed end-to-end dipole correlation. The conditions that protect the edge modes against the adverse perturbations are also identified.