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On the evaluation of the improvement parameter in the lattice Hamiltonian approach to critical phenomena

Massimo Campostrini·Pietro Parruccini·Paolo Rossi
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Abstract

In lattice Hamiltonian systems with a quartic coupling $γ$, a critical value $γ^*$ may exist such that, when $γ=γ^*$, the leading irrelevant operator decouples from the Hamiltonian and the leading nonscaling contribution to renormalization-group invariant physical quantities (evaluated in the critical region) vanishes. The 1/N expansion technique is applied to the evaluation of $γ^*$ for the lattice Hamiltonian of vector spin models with O(N) symmetry. As a byproduct, systematic asymptotic expansions for the relevant lattice massive one-loop integrals are obtained.

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Massimo Campostrini, Pietro Parruccini, Paolo Rossi. 2002-12-12. On the evaluation of the improvement parameter in the lattice Hamiltonian approach to critical phenomena. https://doi.org/10.1103/physreve.67.046121

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