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).