Bloch Oscillations (BOs) of quantum particles manifest themselves as periodic
spreading and re-localization of the associated wave functions when traversing
lattice potentials subject to external gradient forces. Albeit BOs are deeply
rooted into the very foundations of quantum mechanics, all experimental
observations of this phenomenon so far have only contemplated dynamics of one
or two particles initially prepared in separable local states, which is well
described by classical wave physics. Evidently, a more general description of
genuinely quantum BOs will be achieved upon excitation of a Bloch-oscillator
lattice system by nonlocal states, that is, containing correlations in
contradiction with local realism. Here we report the first experimental
observation of BOs of two-particle Einstein-Podolsky-Rosen states (EPR), whose
associated N-particle wave functions are nonlocal by nature. The time evolution
of two-photon EPR states in Bloch-oscillators, whether symmetric, antisymmetric
or partially symmetric, reveals unexpected transitions from particle
antibunching to bunching. Consequently, the initial state can be tailored to
produce spatial correlations akin to bosons, fermions or anyons. These results
pave the way for a wider class of photonic quantum simulators.Comment: 21 pages, 6 figure