In a recent detailed research program we proposed to study the complex
physics of topological phases by an all optical implementation of a
discrete-time quantum walk. The main novel ingredient proposed for this study
is the use of non-linear parametric amplifiers in the network which could in
turn be used to emulate intra-atomic interactions and thus analyze many-body
effects in topological phases even when using light as the quantum walker. In
this paper, and as a first step towards the implementation of our scheme, we
analize the interplay between quantum walk lattice topology and spatial
correlations of bi-photons produced by spontaneous parametric down-conversion.
We also describe different detection methods suitable for our proposed
experimental scheme.Comment: 7 pages, 3 figures. arXiv admin note: substantial text overlap with
arXiv:1409.127