22–26 Sept 2025
RIKEN Kobe Integrated Innovation Building (理化学研究所の神戸キャンパスの融合連携イノベーション推進棟)
Asia/Tokyo timezone

Resonances, Spectral Theory, and the Resurgent Structure

23 Sept 2025, 09:30
1h
8F Lecture theatre (RIKEN Kobe Integrated Innovation Building (理化学研究所の神戸キャンパスの融合連携イノベーション推進棟))

8F Lecture theatre

RIKEN Kobe Integrated Innovation Building (理化学研究所の神戸キャンパスの融合連携イノベーション推進棟)

Kobe Campus, RIKEN 6-7-1 Minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047 Japan

Speaker

Okuto Morikawa

Description

An attempt is made to unify the understanding of resonance phenomena, analytic spectra, and resurgence by developing and applying a mature exact-WKB framework. We begin by formulating non-perturbative resonances in quantum mechanics via the exact WKB method, demonstrated concretely in the inverted Rosen–Morse potential, where barrier resonances and quasi-stationary states are shown to match exact and WKB predictions. Next, we extend this framework to incorporate Zel’dovich regularization, complex scaling, and a modified rigged Hilbert space, thereby clarifying the equivalence and complementarity of these regularization methods and the functional analytic structure they define. Finally, we apply exact WKB and complex scaling to scattering problems, compute the continuum spectrum and the S-matrix, and reinterpret classical theorems such as Aguilar-Balslev-Combes and the Siegert boundary condition in this unified setting. The result is a coherent picture in which resonant poles, continuum spectra, and resurgent structures are seamlessly interconnected, giving new insight into the spectral theory of unstable quantum states.

Presentation materials