  We investigate the interplay between long-range and direct photon-assisted
transport in a triple quantum dot chain where local ac voltages are applied to
the outer dots. We propose the phase difference between the two ac voltages as
an external parameter, which can be easily tuned to manipulate the current
characteristics. For gate voltages in phase opposition we find quantum
destructive interferences analogous to the interferences in closed-loop
undriven triple dots. As the voltages oscillate in phase, interferences between
multiple paths give rise to dark states. Those totally cancel the current, and
could be experimentally resolved.
