Quantum dot dephasing by edge states

We calculate the dephasing rate of an electron state in a pinched quantum d ot, due to Coulomb interactions between the electron in the dot and electro ns in a nearby voltage-biased ballistic nanostructure. The dephasing is cau sed by nonequilibrium time fluctuations of the electron density in the nano structure, which create random electric fields in the dot. As a result, the electron level in the dot fluctuates in time, and the coherent part of the resonant transmission through the dot is suppressed.