Institut für Kernphysik, Technische Universität Darmstadt, Darmstadt, Germany.
Phys Rev Lett. 2012 Jan 13;108(2):024101. doi: 10.1103/PhysRevLett.108.024101. Epub 2012 Jan 10.
We demonstrate the presence of parity-time (PT) symmetry for the non-Hermitian two-state Hamiltonian of a dissipative microwave billiard in the vicinity of an exceptional point (EP). The shape of the billiard depends on two parameters. The Hamiltonian is determined from the measured resonance spectrum on a fine grid in the parameter plane. After applying a purely imaginary diagonal shift to the Hamiltonian, its eigenvalues are either real or complex conjugate on a curve, which passes through the EP. An appropriate basis choice reveals its PT symmetry. Spontaneous symmetry breaking occurs at the EP.
我们证明了在耗散微波弹珠的非厄米二能级哈密顿量附近存在宇称时间（PT）对称性。弹珠的形状取决于两个参数。哈密顿量由在参数平面上的精细网格上测量的共振谱确定。在对哈密顿量施加纯虚对角位移后，其特征值在通过临界点的曲线上为实数或复共轭。适当的基选择揭示了其 PT 对称性。临界点处发生自发对称性破缺。
