Multi-channel analog of the effective-range expansion
2011 (English)In: Journal of Physics A: Mathematical and Theoretical, ISSN 1751-8113, Vol. 44, no 11, 115303- p.Article in journal (Refereed) Published
Similar to the standard effective-range expansion that is done near the threshold energy, we obtain a generalized power-series expansion of the multi-channel Jost-matrix that can be done near an arbitrary point on the Riemann surface of the energy within the domain of its analyticity. In order to do this, we analytically factorize its momentum dependences at all the branching points on the Riemann surface. The remaining single-valued matrix functions of the energy are then expanded in the power series near an arbitrary point in the domain of the complex energy plane where it is analytic. A systematic and accurate procedure has been developed for calculating the expansion coefficients. This means that near an arbitrary point in the domain of physically interesting complex energies it is possible to obtain a semi-analytic expression for the Jost-matrix (and therefore for the S-matrix) and use it, for example, to locate the spectral points (bound and resonant states) as the S-matrix poles.
Place, publisher, year, edition, pages
2011. Vol. 44, no 11, 115303- p.
IdentifiersURN: urn:nbn:se:su:diva-69427DOI: 10.1088/1751-8113/44/11/115303ISI: 000287699800015OAI: oai:DiVA.org:su-69427DiVA: diva2:478274
authorCount :22012-01-162012-01-122012-01-16Bibliographically approved