Session: VIB-03-03: Dynamics & Waves in Solids and Metamaterials III

Paper Number: 97941

97941 - Parity-Time Symmetric Dynamics in Counter-Rotating Gyroscopic Mechanical Systems 

Parity-time (PT) symmetric systems have non-Hermitian Hamiltonians whose observables are real-valued. Most existing designs of PT symmetric systems in electronics, optics, and acoustics rely on an exact balance of loss and gain in the media to achieve PT symmetry. However, the dispersive properties of most loss and gain materials restrict the frequency range where the system is PT symmetric. This makes it challenging to access the exceptional points of the system to observe the PT symmetric transition dynamics. This work proposes a new path to design PT symmetric systems based on gyroscopic effects instead of using loss and gain units. This work demonstrates that PT symmetry and the occurrence of exceptional points are preserved for inversive, counter-rotating gyroscopic systems. In such systems, PT symmetry is independent of material dispersion and the exceptional points can be robustly obtained. In a gyroscopic system with two circular rings rotating in opposite directions at the same speed, the spontaneous symmetry breaking across the exceptional points results in a phase transition from a moving maximum deformation location to a motionless maximum point. The motionless maximum point occurs despite the externally imposed rotation of the two rings. The results set the foundation to study nonlinear dispersive physics in PT symmetric system, including solitary waves and inelastic wave scattering.

Presenting Author: Bin Dong University of Utah

Presenting Author Biography: Postdoctoral Research Associate, University of Utah<br/>Ph.D. in Mechanical Engineering, Virginia Tech<br/>B.S. in Mechanical Engineering, Dalian University of Technology

Authors:

Bin Dong University of Utah
Chengzhi Shi Georgia Institute of Technology
Robert G. Parker University of Utah