Neil P Oxtoby et al 2003 J. Phys.: Condens. Matter 15 8055 doi:10.1088/0953-8984/15/46/020
Neil P Oxtoby1,2, He-Bi Sun1,3 and Howard M Wiseman2
Show affiliationsWe propose a model for non-ideal monitoring of the state of a coupled quantum dot qubit by a quantum tunnelling device. The non-ideality is modelled using an equivalent measurement circuit. This allows realistically available measurement results to be related to the state of the quantum system (qubit). We present a quantum trajectory that describes the stochastic evolution of the qubit state conditioned by tunnelling events (i.e. current) through the device. We calculate and compare the noise power spectra of the current in an ideal and a non-ideal measurement. The results show that when the two qubit dots are strongly coupled the non-ideal measurement cannot detect the qubit state precisely. The limitation of the ideal model for describing a realistic system may be estimated from the noise spectra.
03.67.Lx Quantum computation architectures and implementations
Issue 46 (26 November 2003)
Received 28 July 2003
Published 7 November 2003
Neil P Oxtoby et al 2003 J. Phys.: Condens. Matter 15 8055
J H NamKoong and S H Lim 2009 J. Phys. D: Appl. Phys. 42 225003
Cao Feng et al 2009 Chinese Phys. Lett. 26 114203
A B Voitkiv and J Ullrich 2001 J. Phys. B: At. Mol. Opt. Phys. 34 4513
Ananth N Bhoj and Mark J Kushner 2004 J. Phys. D: Appl. Phys. 37 2510
J Rogel-Salazar et al 2001 J. Phys. B: At. Mol. Opt. Phys. 34 4617
Johan van de Leur 2004 J. Phys. A: Math. Gen. 37 4395
G W Mbise et al 1997 J. Phys. D: Appl. Phys. 30 2103
K O Kvashnina et al 2009 J. Phys.: Conf. Ser. 190 012191
K-M Wang et al 2007 J. Phys. D: Appl. Phys. 40 4740