Aurégan Yves, Pagneux Vincent
Laboratoire d'Acoustique de l'Université du Maine, UMR CNRS 6613 Avenue O Messiaen, F-72085 LE MANS Cedex 9, France.
Phys Rev Lett. 2017 Apr 28;118(17):174301. doi: 10.1103/PhysRevLett.118.174301.
We show theoretically and experimentally that the propagation of an acoustic wave in an airflow duct going through a pair of diaphragms, with equivalent amounts of mean-flow-induced effective gain and loss, displays all the features of a parity-time (PT) symmetric system. Using a scattering matrix formalism, we observe, experimentally, the properties which reflect the PT symmetry of the scattering acoustical system: the existence of spontaneous symmetry breaking with symmetry-broken pairs of scattering eigenstates showing amplification and reduction, and the existence of points with unidirectional invisibility.
我们通过理论和实验表明，声波在穿过一对隔膜的气流管道中传播时，平均流引起的有效增益和损耗等量，呈现出宇称时间（PT）对称系统的所有特征。使用散射矩阵形式，我们通过实验观察到反映散射声学系统PT对称性的特性：存在自发对称性破缺，具有显示放大和衰减的对称破缺散射本征态对，以及存在单向隐形点。
