An Optical System Defies Conventional Band Theory
June 10, 2021•
Physics 14, s70
Squeezed wave functions reshape an open quantum system’s bulk-boundary properties and generate a new class of parity-time symmetry.
L. Xiao
L. Xiao
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Quantum systems that obey parity-time symmetry exhibit “exceptional points” within their parameter space. In quantum optical systems, these are points where a light beam’s energy gains and losses are perfectly balanced, leading to rich critical phenomena, such as extreme sensitivity to external parameters. Parity-time symmetry can be engineered into systems via designs that ensure a balance of inward and outward energy flows (see Viewpoint:
PT Symmetry Goes Quantum). Now, Lei Xiao, at Beijing Computational Science Research Center, and colleagues demonstrate a new way to produce both parity-time symmetry and exceptional points in a quantum-optical circuit. Their study could allow tools for tuning exotic behavior in photonic, phononic, and cold-atom systems [1].