The explorations of parity-time(PT)-symmetric acoustics have resided at the frontier in physics,and the pre-existing accessing of exceptional points typically depends on Fabry-Perot resonances of the coupling interlay...The explorations of parity-time(PT)-symmetric acoustics have resided at the frontier in physics,and the pre-existing accessing of exceptional points typically depends on Fabry-Perot resonances of the coupling interlayer sandwiched between balanced gain and loss components.Nevertheless,the concise PT-symmetric acoustic heterostructure,eliminating extra interactions caused by the interlayer,has not been researched in depth.Here we derive the generalized unitary relation for one-dimensional(1D)PT-symmetric heterostructure of arbitrary complexity,and demonstrate four disparate patterns of anisotropic transmission resonances(ATRs)accompanied by corresponding spontaneous phase transitions.As a special case of ATR,the occasional bidirectional transmission resonance reconsolidates the ATR frequencies that split when waves incident from opposite directions,whose spatial profiles distinguish from a unitary structure.The derived theoretical relation can serve as a predominant signature for the presence of PT symmetry and PT-symmetry-breaking transition,which may provide substantial support for the development of prototype devices with asymmetric acoustic responses.展开更多
基金Project supported by the National Basic Research Program of China(Grant No.2017YFA0303702)the National Natural Science Foundation of China(Grant Nos.12225408,12074183,11922407,11904035,11834008,and 11874215)
文摘The explorations of parity-time(PT)-symmetric acoustics have resided at the frontier in physics,and the pre-existing accessing of exceptional points typically depends on Fabry-Perot resonances of the coupling interlayer sandwiched between balanced gain and loss components.Nevertheless,the concise PT-symmetric acoustic heterostructure,eliminating extra interactions caused by the interlayer,has not been researched in depth.Here we derive the generalized unitary relation for one-dimensional(1D)PT-symmetric heterostructure of arbitrary complexity,and demonstrate four disparate patterns of anisotropic transmission resonances(ATRs)accompanied by corresponding spontaneous phase transitions.As a special case of ATR,the occasional bidirectional transmission resonance reconsolidates the ATR frequencies that split when waves incident from opposite directions,whose spatial profiles distinguish from a unitary structure.The derived theoretical relation can serve as a predominant signature for the presence of PT symmetry and PT-symmetry-breaking transition,which may provide substantial support for the development of prototype devices with asymmetric acoustic responses.
