Complementarity in a Closed-Loop Aharonov-Bohm Interferometer

Abstract

We study complementarity in a two-terminal closed-loop Aharonov-Bohm interferometer with a quantum dot embedded in an arm of the ring and a nearby charge detector capacitively coupled to the quantum dot. We show that perfect charge detection does not give full information of the electronic path, so it does not completely suppress the interference. We propose that this property can be verified even in the limit of weak charge detection by investigating the dephasing of the first and the second harmonics of the Aharonov-Bohm oscillation. The first harmonic of the AB oscillation is reduced monotonically as a function of the charge detection strength. In contrast, the second harmonic interference remains unaffected due to the fact that charge detection is not able to detect the electronic path responsible for the second harmonic. Our theory confirms that the particle-like behavior of an electron emerges from the path information itself rather than from the disturbance.

Single molecular shuttle-junction: Shot noise and decoherence

“…As recently reported, a single vibrational mode of a QD array enhances the electron transport and partially preserves its phase information [95]. The coherent transport of electrons in QDs is also sensitive to spin flip, electron-electron interaction, and external detectors [96][97][98][99][100][101][102][103][104]. A cantilever-based which-path charge detector has been previously studied [105,106]; this detector is based on dot-cantilever coupling, which causes remarkable dephasing to electrons.…”