Full control over the dynamics of interacting, indistinguishable quantum particles is an important prerequisite for the experimental study of strongly correlated quantum matter and the implementation of high-fidelity quantum information processing. Here we demonstrate such control over the quantum walk - the quantum mechanical analogue of the classical random walk - in the strong interaction regime. Using interacting bosonic atoms in an optical lattice, we directly observe fundamental effects such as the emergence of correlations in two-particle quantum walks, as well as strongly correlated Bloch oscillations in tilted optical lattices. Our approach can be scaled to larger systems, greatly extending the class of problems accessible via quantum walks
@article{arxiv.1409.3100,
title = {Strongly Correlated Quantum Walks in Optical Lattices},
author = {Philipp M. Preiss and Ruichao Ma and M. Eric Tai and Alexander Lukin and Matthew Rispoli and Philip Zupancic and Yoav Lahini and Rajibul Islam and Markus Greiner},
journal= {arXiv preprint arXiv:1409.3100},
year = {2015}
}