As a realization of the quantum Zeno effect, we consider electron tunneling
between two quantum dots with one of the dots coupled to a quantum point
contact detector. The coupling leads to decoherence and to the suppression of
tunneling. When the detector is driven with an ac voltage, a parametric
resonance occurs which strongly counteracts decoherence. We propose a novel
experiment with which it is possible to observe both the quantum Zeno effect
and the parametric resonance in electric transport.Comment: 4 pages, 2 figure