Browsing by Author "Niccoli, Giuliano"

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    The composite operator T-Tbar in sinh-Gordon and a series of massive minimal models
    (2006-04-12T11:33:52Z) Delfino, Gesualdo; Niccoli, Giuliano; Physics; Elementary Particle Theory
    The composite operator T\bar{T}, obtained from the components of the energy-momentum tensor, enjoys a quite general characterization in two-dimensional quantum field theory also away from criticality. We use the form factor bootstrap supplemented by asymptotic conditions to determine its matrix elements in the sinh-Gordon model. The results extend to the breather sector of the sine-Gordon model and to the minimal models M_{2/(2N+3)} perturbed by the operator phi_{1,3}.
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    Form factors of descendant operators in the massive Lee-Yang model
    (2005) Delfino, Gesualdo; Niccoli, Giuliano; Mathematics; Mathematical Physics
    The form factors of the descendant operators in the massive Lee-Yang model are determined up to level 7. This is first done by exploiting the conserved quantities of the integrable theory to generate the solutions for the descendants starting from the lowest non-trivial solutions in each operator family. We then show that the operator space generated in this way, which is isomorphic to the conformal one, coincides, level by level, with that implied by the S-matrix through the form factor bootstrap. The solutions we determine satisfy asymptotic conditions carrying the information about the level that we conjecture to hold for all the operators of the model.