Europhys. Lett.
Volume 63, Number 4, August 2003
Page(s) 485 - 491
Section General
Published online 01 November 2003
DOI: 10.1209/epl/i2003-00567-2
Europhys. Lett., 63 (4) , pp. 485-491 (2003)

Charge transfer counting statistics revisited

A. Shelankov1, 2 and J. Rammer1

1  Department of Physics, Umeå University - 901 87 Umeå, Sweden
2  A. F. Ioffe Physico-Technical Institute - 194021 St. Petersburg, Russia

(Received 4 June 2003; accepted 11 June 2003)

Charge transfer statistics of quantum particles is obtained by analysing the time evolution of the many-body wave function. Exploiting properly chosen gauge transformations, we construct the probabilities for transfers of a discrete number of particles. Generally, the derived formula for counting statistics differs from the one previously obtained by Levitov et al. (J. Math. Phys. , 37 (1996) 4845). The two formulae agree only if the initial state is prohibited from being a superposition of different charge states. Their difference is illustrated for cases of a single particle and a tunnel junction, and the role of charge coherence is demonstrated.

03.65.Ta - Foundations of quantum mechanics; measurement theory.
05.60.Gg - Quantum transport.
42.50.Lc - Quantum fluctuations, quantum noise, and quantum jumps.

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