The question of testing the nonlocality of a single photon has raised much
debate over the last years. The controversy is intimately related to the issue
of providing a common reference frame for the observers to perform their local
measurements. Here we address this point by presenting a simple scheme for
demonstrating the nonlocality of a single photon which does not require a
shared reference frame. Specifically, Bell inequality violation can be obtained
with certainty with unaligned devices, even if the relative frame fluctuates
between each experimental run of the Bell test. Our scheme appears feasible
with current technology, and may simplify the realization of quantum
communication protocols based on single-photon entanglement.Comment: 5 pages, 3 figure
