Quantum limit of measurement and the projection postulate
arXiv:quant-ph/0507197 · doi:10.1142/S0217979206033978
Abstract
We study an electrostatic qubit monitored by a point-contact detector. Projecting an entire qubit-detector wave function on the detector eigenstates we determine the precision limit for the qubit measurements, allowed by quantum mechanics. We found that this quantity is determined by qubit dynamics as well as decoherence, generated by the measurement. Our results show how the quantum precision limit can be improved by a proper design of a measurement procedure.
References added, typo-errors corrected. This paper is based on work presented at the 9th International Conference on Squeezed States and Uncertainty Relations, Besancon, France, May 2-6, 2005. To be published in Special issue of the Journal of Optics B: Quantum and Semiclassical Optics, May 2006