Jean-Loïc will entertain
us with the "Renormalization group optimized perturbation at zero and finite temperature".
He will illustrate how the renormalization group optimized perturbation (RGOPT) resums perturbative expansions in vacuum
or thermal field theories. For zero-temperature QCD the non-perturbative quark condensate is calculated via the spectral density
of the Dirac operator, with good convergence properties exhibited from two-loop to five-loop orders. In thermal QCD the convergence
of thermodynamic quantities is drastically improved already from two-loop RGOPT as compared to standard thermal perturbation,
and it compares much better to lattice simulations. It also cures the bad renormalization scale dependence observed in other
resummation methods known as hard-thermal-loop (HTL) perturbation. If time allows, work in progress needed in gauge theories to go beyond present results will be sketched.
Based on J-L. Kneur, A. Neveu, Phys. Rev. D 101, 074009 https://arxiv.org/abs/2001.11670
J-L. Kneur, M.B. Pinto, T. Restrepo,
L. Fernandez, J-L. Kneur, M.B. Pinto, in preparation.
*tea/coffee/biscuits break at your convenience time
---------Pour plus d'informations, merci de contacter Moultaka G.