ar X iv : h ep - l at / 9 50 80 28 v 1 2 9 A ug 1 99 5
نویسندگان
چکیده
We define a fixed point topological charge for the two–dimensional O(3) lattice σ–model which is free of topological defects. We use this operator in combination with the fixed point action to measure the topological susceptibility for a wide range of correlation lengths. The results strongly suggest that it is not a physical quantity in this model. The procedure, however, can be applied to other asymptotically free theories as well. Work supported in part by Schweizerischer Nationalfonds On leave from the Institute of Theoretical Physics, Eötvös University, Budapest
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