Topological Quantum Optics in Two-Dimensional Atomic Arrays
Snapshot of the time evolution (at t = 5.7 Γ0−1) of the system as an atom on the edge (red star) is driven by a laser (inset). The color code shows the excitation probability | 〈ψ(t)|σ1+ 〉 |2 + | 〈ψ(t)|σ1- 〉 |2at each atomic site i = 1,..., N. Approximately 96% of the emitted excitation is coupled into the forward direction and scattering into bulk and backward edge modes is strongly suppressed. The excitation goes around corners and routes around the large lattice defect.*
In a new paper in Physical Review Letters, physicists in Prof. Mikhail Lukin's group, together with collelagues from Spain and Austria, propose a platform for studying topological effects in quantum optical systems which involves 2D atomic emitter arrays in optical lattices.
They demonstrate that two-dimensional atomic emitter arrays with subwavelength spacing constitute topologically protected quantum optical systems where the photon propagation is robust against large imperfections while losses associated with free space emission are strongly suppressed. Breaking time-reversal symmetry with a magnetic field results in gapped photonic bands with nontrivial Chern numbers and topologically protected, long-lived edge states. Due to the inherent nonlinearity of constituent emitters, such systems provide a platform for exploring quantum optical analogs of interacting topological systems.
*See J. Perczel, J. Borregaard, D.E. Chang, H. Pichler, S.F. Yelin, P. Zoller, and M.D. Lukin, "Topological Quantum Optics in Two-Dimensional Atomic Arrays," Phys. Rev. Lett. 119, 023603 (2017) DOI:https://doi.org/10.1103/PhysRevLett.119.023603