https://doi.org/10.1140/epja/i2013-13032-9
Regular Article - Theoretical Physics
On the ambiguities of sign determination of the S-matrix from energy levels in a finite box
Departamento de Física Teórica and IFIC, Centro Mixto Universidad de Valencia-CSIC, Institutos de Investigación de Paterna, Aptdo. 22085, 46071, Valencia, Spain
* e-mail: oset@ific.uv.es
Received:
26
November
2012
Revised:
11
January
2013
Accepted:
29
January
2013
Published online:
11
March
2013
In a recent paper the authors make a study on the determination of the S-matrix elements for scattering of particles in the infinite volume from the energy levels in a finite box for the case of multiple channels. The study is done with a toy model in 1+1 dimension and the authors find that there is some ambiguity in the sign of nondiagonal matrix elements, casting doubts on whether the needed observables in the infinite volume can be obtained from the energy levels of the box. In this paper I present an easy derivation, confirming the ambiguity of the sign and argue that this, however, does not put restrictions in the determination of observables.
© SIF, Springer-Verlag Berlin Heidelberg, 2013
