Sinica-NCTS Geometry and Quantum Physics Seminar
主講者: | 李瑞光 (國立清華大學) |
講題: | Reflecting on an alternative (parity-time-symmetric) quantum theory, and its analog in optics |
時間: | 2018-03-20 (Tue.) 11:00-12:30 |
地點: | 數學所 617 研討室 (台大院區) |
Abstract: | By no-signaling principle, we showed that parity-time (PT)-symmetric quantum theory as an extension of the quantum theory to non-Hermitian Hamiltonians is either a trivial extension or likely false as a fundamental theory [1]. In addition to the implementation PT-symmetric optical systems by carefully and actively controlling the gain and loss, we show that a 2 × 2 PT-symmetric Hamiltonian has a unitarily equivalent representation without complex optical potentials in the resulting optical coupler. Through the Naimark dilation in operator algebra, passive PT-symmetric couplers can thus be implemented with a refractive index of real values and asymmetric coupling coefficients [2]. Moreover, with a phase-space representation on the vicinity of an exceptional point, we show that a PT-symmetric phase transition from an unbroken PT-symmetry phase to a broken one is a second-order phase transition [3].
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