Crossover from a delocalized to localized atomic excitation in an atom–waveguide interface. (13th May 2021)

• Record Type: Journal Article
• Authors: Jen, H H; You, J-S
• Is Part Of: Journal of physics. Volume 54:Number 10(2021)
• Publication Date: 2021-05-13
• Subjects: delocalized to localized atomic excitation -- atom–waveguide interface -- long-range dipole–dipole interactions -- level statistics; Atoms -- Periodicals; Molecules -- Periodicals; Optics -- Periodicals; Nuclear physics -- Periodicals; 539.6
• DOI: 10.1088/1361-6455/abf6b7
• Languages: English
• ISSNs: 0953-4075

Abstract

Abstract: An atom–waveguide system, which presents one of the quantum interfaces that enable strong couplings between light and atoms, can support tightly-confined guided modes of light. In this distinctive quantum interface, we theoretically investigate the crossover from a delocalized to localized atomic excitation under long-range dipole–dipole interactions and lattice disorders. Both localization lengths of the excitation distributions and power-law scalings of dissipative von Neumann entanglement entropy show signatures of this crossover. We further calculate numerically the level statistics of the underlying non-Hermitian Hamiltonian, from which as the disorder strength increases, the gap ratio decreases and the intrasample variance increases before reaching respective saturated values. The mean gap ratio in the deeply localized regime is close to the one from Poisson statistics along with a relatively large intrasample variance, whereas in the nondisordered regime, a significant level repulsion emerges. Our results provide insights to study the non-ergodic phenomenon in an atom–waveguide interface, which can be potentially applied to photon storage in this interface under dissipations.