Aspects of duality and confining strings

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