Quantum Measurement in Electric Circuit
Abstract
We study fluctuations of electric current in a quantum resistor and derive a general quantummechanical formula for the distribution of transmitted charge. For that we introduce a scheme of current measurement that involves a spin $1/2$ coupled to the current so that it precesses at the rate proportional to the current. Our approach allows the study of charge transfer without breaking the circuit. We analyze a single channel conductor and derive electron counting statistics for arbitrary relation between temperature and voltage. For a perfectly transmitting channel the counting distribution is gaussian, both for zeropoint fluctuations and at finite temperature. At constant voltage and low temperature the distribution is binomial, i.e., it arises from Bernoulli statistics.
 Publication:

arXiv eprints
 Pub Date:
 January 1994
 arXiv:
 arXiv:condmat/9401004
 Bibcode:
 1994cond.mat..1004L
 Keywords:

 Condensed Matter
 EPrint:
 10 pages, RevTeX 3.0