title: Accessing the exceptional points of parity-time symmetric acoustics.
abstract: Parity-time (PT) symmetric systems experience phase transition between PT exact and broken phases at exceptional point. These PT phase transitions contribute significantly to the design of single mode lasers, coherent perfect absorbers, isolators, and diodes. However, such exceptional points are extremely difficult to access in practice because of the dispersive behaviour of most loss and gain materials required in PT symmetric systems. Here we introduce a method to systematically tame these exceptional points and control PT phases. Our experimental demonstration hinges on an active acoustic element that realizes a complex-valued potential and simultaneously controls the multiple interference in the structure. The manipulation of exceptional points offers new routes to broaden applications for PT symmetric physics in acoustics, optics, microwaves and electronics, which are essential for sensing, communication and imaging.
authors.affiliation: NSF Nano-scale Science and Engineering Center (NSEC), University of California, Berkeley, 3112 Etcheverry Hall, Berkeley, California 94720, USA.
authors.forename: Chengzhi
authors.initials: C
authors.lastname: Shi
authors.affiliation: NSF Nano-scale Science and Engineering Center (NSEC), University of California, Berkeley, 3112 Etcheverry Hall, Berkeley, California 94720, USA.
authors.forename: Marc
authors.initials: M
authors.lastname: Dubois
authors.affiliation: State Key Laboratory of ASIC and System, Department of Microelectronics, Fudan University, 201203 Shanghai, China.
authors.forename: Yun
authors.initials: Y
authors.lastname: Chen
authors.affiliation: State Key Laboratory of ASIC and System, Department of Microelectronics, Fudan University, 201203 Shanghai, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Cheng
authors.affiliation: NSF Nano-scale Science and Engineering Center (NSEC), University of California, Berkeley, 3112 Etcheverry Hall, Berkeley, California 94720, USA.
authors.forename: Hamidreza
authors.initials: H
authors.lastname: Ramezani
authors.affiliation: NSF Nano-scale Science and Engineering Center (NSEC), University of California, Berkeley, 3112 Etcheverry Hall, Berkeley, California 94720, USA.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Wang
authors.affiliation: NSF Nano-scale Science and Engineering Center (NSEC), University of California, Berkeley, 3112 Etcheverry Hall, Berkeley, California 94720, USA.|Materials Science Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, USA.|Department of Physics, King Abdulaziz University, Jeddah 21589, Saudi Arabia.
authors.forename: Xiang
authors.initials: X
authors.lastname: Zhang