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Correlations in quantum systems and branch points in the complex plane

I. Rotter
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Abstract

Branch points in the complex plane are responsible for avoided level crossings in closed and open quantum systems. They create not only an exchange of the wave functions but also a mixing of the states of a quantum system at high level density. The influence of branch points in the complex plane on the low-lying states of the system is small.

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I. Rotter. 2001-07-04. Correlations in quantum systems and branch points in the complex plane. https://doi.org/10.1103/physrevc.64.034301

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