Anti-parity–time symmetry with flying atoms

By Peng Peng, Wanxia Cao, Ce Shen, Weizhi Qu, J. Wen, Liang Jiang, Yanhong Xiao. Nature Physics, 2015

418 citations recorded by the source corpus.

The recently developed notion of parity–time (PT) symmetry in optical systems has spawned intriguing prospects. So far, most experimental implementations have been reported in solid-state systems. Here, we report the first experimental demonstration of optical anti-PT symmetry—the counterpart of conventional PT symmetry—in a warm atomic-vapour cell. Rapid coherence transport via flying atoms leads to a dissipative coupling between two long-lived atomic spin waves, allowing for the observation of the essential features of anti-PT symmetry with unprecedented precision on the phase-transition threshold, as well as refractionless light propagation. Moreover, we show that a linear or nonlinear interaction between the two spatially separated beams can be achieved. Our results advance non-Hermitian physics by bridging to the field of atomic, molecular and optical physics, where new phenomena and applications in quantum and nonlinear optics aided by (anti-)PT symmetry could be anticipated. Parity–time symmetry in optics is studied in a warm atomic vapour, where its counterpart, anti-parity–time symmetry, as well as refractionless propagation, can also be observed.

Subfields: Atomic and Molecular Physics, and Optics, Statistical and Nonlinear Physics

View Paper: https://www.semanticscholar.org/paper/59f81e2533ca8de0b2f4e4f4a257190128576913

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Citations in the corpus

Exceptional points in optics and photonics (2019, background): “In this regard, the realization of complex potentials supporting exceptional points have been theoretically proposed in three- and four-level atoms (79, 80) and experimentally demonstrated in coupled atomic vapor cells (81), as well as in PTsymmetric optical lattices (82).”
Topological Phases of Non-Hermitian Systems (2018, background): “(38)], a PTsymmetry-breaking (an anti-PT-symmetry-breaking [77]) transition across an exceptional point can be identified as a topological transition.”
Coherent perfect absorption at an exceptional point (2021, background): “Moreover, since the onset of laser emission corresponds to the non-generic case in which a resonance exists at a real frequency (20), an EP for two resonances engineered to have frequencies at or very near the real axis leads to unusual lasing behavior, including chiral laser emission (21, 22), lase”
Symmetry and Topology in Non-Hermitian Physics (2018, background): “[85] P.”