Non‐Hermitian Superradiance Lattices with Room‐Temperature Atoms

Abstract

Composed of some collective excited states of an atomic ensemble, a superradiance lattice can be considered as an infinite tight‐binding model in momentum space. In this work, a non‐Hermitian superradiance lattice is realized by introducing state‐selective dissipation rates, using room‐temperature atoms. The steady‐state response of such a non‐Hermitian momentum lattice is studied with non‐Hermitian absorption spectroscopy both theoretically and experimentally. A pit‐to‐peak transition in the spectroscopy is observed when the introduced dissipation rates are tuned. Further, by accounting for the thermal motion of atoms, the Wannier Stark ladders and biorthogonal Berry phases are measured. This work hence realizes a quantum platform that can be highly useful for future experimental simulation of non‐Hermitian physics (e.g., non‐Hermitian topological lattice) with room‐temperature atoms.