  The discovery of the intriguing phenomenon that certain kinds of quantum
correlations remain impervious to noise up to a specific point in time and then
suddenly decay, has generated immense recent interest. We exploit dynamical
decoupling sequences to prolong the persistence of time-invariant quantum
discord in a system of two NMR qubits decohering in independent dephasing
environments. We experimentally prepare two-qubit Bell-diagonal quantum states
that interact with individual dephasing channels and demonstrate the effect of
dynamical decoupling on the preservation of both quantum and classical
correlations. We are able to freeze quantum discord over long time scales in
the presence of noise, using dynamical decoupling. We use robust
state-independent dynamical decoupling schemes for state preservation and
demonstrate that these schemes are able to successfully preserve quantum
discord.
