Aspects of duality and confining strings

We inspect the energy spectrum of a confining string, at the classical leve l in an effective field theory model, The spectrum can be characterized by a spectral function, and twisting and bending of the string is manifested b y the invariance of this function under a duality transformation. Both gene ral considerations and numerical simulations reveal that the spectral funct ion can be approximated by a simple rational form. (C) 2000 Elsevier Scienc e B.V. All rights reserved.