| Based on the background of non-Hermitian quantum mechanics,the non-Hermitian Hamiltonian studied has a real spectrum when it satisfies the invariant condition of parity-time inversion.The response characteristics of the system before and after the anti-parity-time symmetry breaking were observed by electronic circuit experiments.This thesis introduces non-Hermitian physics,correlation properties of parity time symmetry and anti-parity time symmetry,and the properties near the exception point in parity time symmetry are also discussed,enhanced system sensitivity.In this thesis,RLC resonant element is used to realize the anti-parity-time symmetric circuit of second-order exception points.The response of the anti-parity-time symmetric circuit of second-order exception points is theoretically analyzed by Kirchhoff’s law.The intrinsic frequency evolution curve of the circuit system is verified by theoretical calculation,circuit simulation and experiment.In this thesis,the sublinear phenomena caused by small perturbations near the exceptional points are analyzed theoretically,and the sensitivity of the system near the second-order exceptional points is obtained.Compared with the sensitivity of the pure dissipative system,the sensitivity of the system near the second-order exceptional point is better than that of the traditional pure dissipative system.In order to verify that the symmetric circuit after PT inversion satisfies the anti-parity-time symmetry,a symmetric circuit after PT inversion is proposed.The intrinsic frequency evolution of the anti-parity-time symmetric circuit after PT reversal is verified by theoretical calculation,circuit simulation and experiment.A third-order anti-parity-time symmetric circuit is designed.Theoretical calculation,circuit simulation and experiment verify that the third order anti-parity-time symmetric circuit has specific intrinsic frequency and sublinear response near the exception point.Compared with the second-order anti-parity-time symmetric circuit,it is found that the higher order exception points can significantly enhance the sensitivity of the system.In this thesis,the theory,simulation and experimental results of each circuit system are described in detail... |
