  Within the lowest-order Born approximation, we calculate the exact dynamics
of a single qubit in the presence of 1/f noise, without making any Markov
approximation. We show that the non-Markovian qubit time-evolution exhibits
asymmetries and beatings that cannot be explained within a Markovian theory.
The present theory for 1/f noise is relevant for both spin- and superconducting
qubit realizations in solid-state devices, where 1/f noise is ubiquitous.
