2005/10/31 by Andrew N. Jordan, Alexander N. Korotkov, Markus Buttiker · 2 citations
Physics and Astronomy · #cond-mat.mes-hall #quant-ph
paper · pdf · doi:10.1103/physrevlett.97.026805
published as Phys. Rev. Lett. 97, 026805 (2006) · 4 pages, 3 figures, published version
arxiv created 2006/08/10 · arxiv updated 2009/12/01
A kicked quantum nondemolition measurement is introduced, where a qubit is weakly measured by pumping current. Measurement statistics are derived for weak measurements combined with single qubit unitary operations. These results are applied to violate a generalization of Leggett and Garg's inequality. The violation is related to the failure of the noninvasive detector assumption, and may be interpreted as either intrinsic detector backaction, or the qubit entangling the microscopic detector excitations. The results are discussed in terms of a quantum point contact kicked by a pulse generator, measuring a double quantum dot.