Dephasing and ac oscillations in an open Aharanov–Bohm ring

We have studied the tunneling current in an open ring system enclosing a magnetic flux which may have an ac component. Analytic expressions for the time-averaged tunneling current have been obtained, which suggest two possible experiments to determine the temperature dependence of the dephasing rate. We have also discovered a new phenomenon that with a given dc magnetic flux, the current is an oscillating function of the ac magnetic flux, but with decaying amplitude of oscillation. This result is also observable experimentally.