Quantum mechanics helps efficient charge detection

Single electron detection is an important task in quantum information
processing. Quite generally, single electrons in a charged object can be
detected by capacitively coupling a detector circuit to the object. In
this talk, I describe how the quantum mechanics helps single electron
detection in terms of sensitivity and efficiency. The concept of
dephasing and information acquisition rates are introduced. In
particular, I discuss the role of quantum interference [1, 2, 3] and
entanglement [3, 4] for improving the sensitivity and efficiency of
single charge detection.

[1] Kicheon Kang, \"Decoherence of the Kondo singlet via a quantum point
contact detector\", Phys. Rev. Lett. 95, 206808 (2005).
[2] D. I. Chang et al., \"Quantum mechanical complementarity probed in a
closed-loop Aharonov-Bohm interferometer\", Nature Physics 4, 205 (2008).
[3] P.K. Pathak and Kicheon Kang, \"Edge-state Fabry-Perot interferometer
as a high-sensitivity charge detector\", Phys. Rev. B 79, 233302 (2009).
[4] Y. Lee, G. L. Khym, and Kicheon Kang, \"Exchange statistics, charge
detection and back-action dephasing by a mesoscopic beam collider \", J.
Phys. Condens. Matter 20, 395212 (2008).