Multipartite entanglement generation via quantum walks with multiple coins

Abstract

We show that strongly correlated n-qubit states emerge in the multi-coin long-cycle quantum walk protocol after measuring the spatial particle in the limit of many iteration steps. The ensemble-averaged characteristics of such multipartite correlations tend to steady values with low relative fluctuations. For two-qubit interactions, the average concurrence tends to a constant value, with the standard deviation decreasing with the size of the cycle. In the n-qubit case, the global correlation measure exhibits the emergence of strongly correlated states for a large number of qubits.