  We experimentally emulate interaction induced blockade and local spin
freezing in two and three qubit Nuclear Magnetic Resonance (NMR) architecture.
These phenomena are identical to the Rydberg blockade and Rydberg biased
freezing. In Rydberg blockade, the simultaneous excitation of two or more atoms
is blocked due to the level shift induced by the strong Van der Waal's
interaction. In such a strong interaction regime, one can also observe Rydberg
biased freezing, wherein the dynamics is confined to a subspace, with the help
of multiple drives with unequal amplitudes. Here we drive NMR qubits with
specific transition-selective radio waves, while intermittently characterizing
the quantum states via quantum state tomography. This not only allows us to
track the population dynamics, but also helps to probe quantum correlations, by
means of quantum discord, evolving under blockade and freezing phenomena.
While, our work constitutes the first experimental simulations of these
phenomena in the NMR platform, it is also the first experimental demonstration
of Rydberg biased freezing. Moreover, these studies open up interesting quantum
control perspectives in exploiting the above phenomena for entanglement
generation as well as subspace manipulations.
