title: Strong Levinson theorem for the Dirac equation.
abstract: We consider the Dirac equation in one space dimension in the presence of a symmetric potential well. We connect the scattering phase shifts at E= +m and E= -m to the number of states that have left the positive energy continuum or joined the negative energy continuum, respectively, as the potential is turned on from zero.
authors.affiliation: Physics and Astronomy Department, University of Sussex, Brighton BN1 9QH, United Kingdom. a.calogeracos@sussex.ac.uk
authors.forename: Alex
authors.initials: A
authors.lastname: Calogeracos
authors.forename: Norman
authors.initials: N
authors.lastname: Dombey