English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Within the theory of Siegert pseudostates, it is possible to accuratelycalculate bound states and resonances. The energy continuum is replaced by adiscrete set of states. Many questions of interest in scattering theory can beaddressed within the framework of this formalism, thereby avoiding the need totreat the energy continuum. For practical calculations it is important to knowwhether a certain subset of Siegert pseudostates comprises a basis. This is anontrivial issue, because of the unusual orthogonality and overcompletenessproperties of Siegert pseudostates. Using analytical and numerical arguments,it is shown that the subset of bound states and outgoing Siegert pseudostatesforms a basis. Time evolution in the context of Siegert pseudostates is alsoinvestigated. From the Mittag-Leffler expansion of the outgoing-wave Green'sfunction, the time-dependent expansion of a wave packet in terms of Siegertpseudostates is derived. In this expression, all Siegert pseudostates--bound,antibound, outgoing, and incoming--are employed. Each of these evolves in timein a nonexponential fashion. Numerical tests underline the accuracy of themethod

Siegert pseudostates: Completeness and time evolution