2021/06/30 by Florian Koch, Jan Carl Budich
Mathematics · Physics and Astronomy · #Boundary (topology) #Context (archaeology) #Coupling (piping) #Hermitian matrix #Mathematical analysis #Mathematics #Mechanical and Optical Resonators #Observable #Physics #Quantum #Quantum Mechanics and Non-Hermitian Physics #Quantum limit #Quantum mechanics #Symmetry protected topological order #Topological Materials and Phenomena #Topological degeneracy #Topological insulator #Topological order #Topological quantum number #Topology (electrical circuits) #cond-mat.mes-hall #physics.ins-det #physics.optics #quant-ph
paper · pdf · doi:10.1103/physrevresearch.4.013113
published as Phys. Rev. Research 4, 013113 (2022) · 5+4 pages, 4 figures, v2: updated to the published version
openalex publication_date 2022/02/11 · arxiv created 2022/02/14 · arxiv updated 2022/02/15 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We investigate in the framework of quantum noise theory how the striking boundary sensitivity recently discovered in the context of non-Hermitian (NH) topological phases may be harnessed to devise novel quantum sensors. Specifically, we study a quantum-optical setting of coupled modes arranged in an array with broken ring geometry that would realize a NH topological phase in the classical limit. Using methods from quantum-information theory of Gaussian states, we show that a small coupling induced between the ends of the broken ring may be detected with a precision that increases exponentially in the number of coupled modes, e.g., by heterodyne detection of two output modes. While this robust effect only relies on reaching a NH topological regime, we identify a resonance phenomenon without direct classical counterpart that provides an experimental knob for drastically enhancing the aforementioned exponential growth. Our findings pave the way towards designing quantum NH topological sensors that may observe with high precision any physical observable that couples to the boundary conditions of the device.