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Particle Content of the Nonlinear Sigma Model with Theta-Term: a Lattice Model Investigation

L. Campos Venuti·C. Degli Esposti Boschi·E. Ercolessi·F. Ortolani·G. Morandi·S. Pasini·M. Roncaglia
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Abstract

Using new as well as known results on dimerized quantum spin chains with frustration, we are able to infer some properties on the low-energy spectrum of the O(3) Nonlinear Sigma Model with a topological theta-term. In particular, for sufficiently strong coupling, we find a range of values of theta where a singlet bound state is stable under the triplet continuum. On the basis of these results, we propose a new renormalization group flow diagram for the Nonlinear Sigma Model with theta-term.

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L. Campos Venuti, C. Degli Esposti Boschi, E. Ercolessi, F. Ortolani, G. Morandi, S. Pasini, M. Roncaglia. 2005-01-21. Particle Content of the Nonlinear Sigma Model with Theta-Term: a Lattice Model Investigation. https://doi.org/10.1088/1742-5468%2F2005%2F02%2Fl02004

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