A naive application of Fermi's Golden rule (FGR)  suggests that weakly interacting lattice fermions should have a lifetime ~ 1/Delta^2 in the limit of small interaction strength Delta, and at finite temperature T>0. Based on dissipation-assisted-operator-evolution (DAOE) numerical results, and two rather different non-perturbative diagrammatic re-summations, we predict that the quasiparticle lifetime is suppressed by an additional logarithmic factor so that lifetime ~ 1/[(Delta^2 \log(1/|\Delta|)] in 1 spatial dimension.

 

Authors: Thomas Young, Jerome Lloyd, Curt von Keyserlingk

[This work is not yet published.]