2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/43091The problem of quantum fluctuations of the chiral condensate due to next-to-leading contributions is investigated. Meson contributions to the chiral condensate are calculated in the Nambu--Jona-Lasinio model with the analytical (dimensional) regularization in a framework of the mean-field expansion. The pion contribution can be significant, while the sigma-meson contribution is small in the regime of physical values of the model parameters. Non-pole contributions are also estimated and found to be small.5 pages, no figures, Talk given at XVII International Workshop on High Energy Physics and Quantum Field Theory (QFTHEP'2003), Samara--Saratov, 4-11 Sept. 2003High Energy Physics - Phenomenologytext