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arXiv · 2307.12021

Dynamics in non-Hermitian systems with nonreciprocal coupling

Jung-Wan Ryu
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Abstract

We reveal that non-Hermitian Hamiltonians with nonreciprocal coupling can achieve amplification of initial states without external gain due to a kind of inherent source. We discuss the source and its effect on time evolution in terms of complex eigenenergies and non-orthogonal eigenstates. Demonstrating two extreme cases of Hamiltonians, namely one having complex eigenenergies with orthogonal eigenstates and one having real eigenenergies with non-orthogonal eigenstates, we elucidate the differences between the amplifications from complex eigenenergies and from non-orthogonal eigenstates.

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Jung-Wan Ryu. 2023-07-22. Dynamics in non-Hermitian systems with nonreciprocal coupling. https://doi.org/10.1103/physreva.108.052205

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