Quantum Ising dynamics and Majorana-like edge modes in the Rabi lattice model

by Brijesh Kumar (Jawaharlal Nehru University, New Delhi, India)

Thursday 6 Jun 2013, 11:15 → 12:15 Europe/Zurich

EPFL. SAlle 727 du BSP (EPFL. SAlle 727 du BSP)

We present a case for the realization of Majorana-like fermion modes, through the quantum Ising (QI) dynamics, in the Rabi lattice. A Rabi lattice is an array of the Rabi quantum cavities where each cavity has a two-level atom (or a spin-1/2) coupled via dipole interaction to a single photon (bosonic) mode, and the inter-cavity coupling causes photon hopping. We show that the Rabi lattice model rigorously tends to the QI model in the limit of strong atom-photon coupling. This QI dynamics drives the para- to ferro-electric quantum phase transition in the Rabi lattice, and also guarantees two Majorana-like edge fermions in the ordered phase in one dimension (on an open chain). We identify an observable signature of these modes, and check their stability against the detrimental perturbations such as a stray electric field. We find that the QI Majorana modes are not as fragile as one believed, despite no topological protection.