Exceptional Points as Drivers of Dynamical Phase Transitions: High-Order Singularities in Topological Quantum Systems

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日期	2026-04-27

時間	12:10-13:10

地點	R36173, 1F, Dept. of Physics, Building of Science College, NCKU

領域	Quantum Information Science

講者	姚權哲博士 - 國立成功大學工科系

題目	Exceptional Points as Drivers of Dynamical Phase Transitions: High-Order Singularities in Topological Quantum Systems

摘要	Despite extensive studies on exceptional points (EPs), their microscopic role in driving nonequilibrium dynamical phase transitions remains elusive. We demonstrate that EPs serve as fundamental drivers of these transitions in structured open quantum systems. By establishing a general framework that unifies the description of EPs arising from the coalescence of resonances in gapless media and antibound states in gapped systems, we reveal that EPs strictly govern the critical transition between non-Markovian localization and delocalization phases. This mechanism imprints a characteristic algebraic signature on the dynamics, which smooths the critical crossover into the universal band-edge decay. Our approach remains robust in complex systems exhibiting multiple energy gaps, revealing a fourth-order EP in a topological Ising chain and demonstrating how high-order non-Hermitian degeneracies emerge naturally from the unitary dynamics of structured many-body systems.

2026-04-27 12:10:00 ~ 2026-04-27 13:10:00