Rydberg blockade of atomic ensemble qubits*

We demonstrate \textbar W\textgreater state encoding of multi-atom ensemble qubits. Using optically trapped Rb atoms the T2 coherence time is 2.6(3) ms for an average ensemble number of N $=$ 7.6 atoms and scales approximately inversely with N. Strong Rydberg blockade between two ensemble qubits is demonstrated with a fidelity of 0.89(1) and a fidelity of $\sim $1.0 when postselected on control ensemble excitation. We will present progress towards entanglement of two ensemble qubits using the Rydberg blockade interaction.