2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/95381We consider quantum kinetics of an open quantum system in the presence of periodic fields designed to suppress the internal evolution and shield the system from generic low-frequency environment (refocusing or dynamical decoupling in application to multi-qubit systems). Assuming that the refocusing has order K, that is, for frozen environment the cumulant expansion of the evolution operator over the period tau begins with the term ~tau^(K+1), we trace the associated cancellations in the kernel of the quantum kinetic equation in the Floquet formalism and characterize the remaining decoherence processes.12 pages, 7 eps figuresQuantum Physicstext