Quantum correlations in continuous-time quantum walks of two indistinguishable particles

We evaluate the degree of quantum correlation between two fermions (bosons) subject to continuous-time quantum walks in a one-dimensional (1D) ring lattice with periodic boundary conditions. In our approach, no particle-particle interaction is considered. We show that the interference effects due to exchange symmetry can result into the appearance of nonclassical correlations. The role played onto the appearance of quantum correlations by the quantum statistics of the particles, the boundary conditions, and the partition of the system is widely investigated. Quantum correlations have also been investigated in a model mimicking the ballistic evolution of two indistinguishable particles in a 1D continuous-space structure. Our results are consistent with recent quantum optics and electron quantum optics experiments where the showing up of two-particle nonclassical correlations has been observed even in the absence of mutual interaction between the particles.