Exotic interactions mediated by a non-Hermitian photonic bath

Abstract

Photon-mediated interactions between quantum emitters in engineered photonic baths is an emerging area of quantum optics. At the same time, non-Hermitian (NH) physics is currently thriving, spurred by the exciting possibility to access new physics in systems ruled by non-trivial NH Hamiltonians - in particular photonic lattices - which can challenge longstanding tenets such as the Bloch theory of bands. Here, we combine these two fields and study the exotic interaction between emitters mediated by the photonic modes of a lossy photonic lattice described by a NH Hamiltonian. We show in a paradigmatic case study that structured losses in the field can seed exotic emission properties. Photons can mediate dissipative, fully non-reciprocal, interactions between the emitters with range critically dependent on the loss rate. When this loss rate corresponds to a bare-lattice exceptional point, the effective couplings are exactly nearest-neighbour, implementing a dissipative, fully non-reciprocal, Hatano-Nelson model. Counter-intuitively, this occurs irrespective of the lattice boundary conditions. Thus photons can mediate an effective emitters' Hamiltonian which is translationally-invariant despite the fact that the field is not. We interpret these effects in terms of metastable atom-photon dressed states, which can be exactly localized on only two lattice cells or extended across the entire lattice. These findings introduce a new paradigm of light-mediated interactions with unprecedented features such as non-reciprocity, non-trivial dependence on the field boundary conditions and range tunability via a loss rate.

8+7 pages, 8 figures. Close to published version

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• Engineering and harnessing giant atoms in high-dimensional baths: a cold atoms' implementation
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Cited by in corpus (10)

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• Anomalous Behaviors of Quantum Emitters in Non-Hermitian Baths
• Bound states and photon emission in non-Hermitian nanophotonics
• Unconventional Quantum Electrodynamics with Hofstadter-Ladder Waveguide
• Topological Effects in Two-Dimensional Quantum Emitter Systems
• Fractional Quantum Zeno Effect Emerging from Non-Hermitian Physics
• Quantum Metric Unveils Defect Freezing in Non-Hermitian Systems
• Lindblad master equations for quantum systems coupled to dissipative bosonic modes