Noise in detection of qubit states using a quantum point contact

Oxtoby, N. P., Sun, H. and Wiseman, H. M. (2003). Noise in detection of qubit states using a quantum point contact. In: Proceedings of SPIE - The International Society for Optical Engineering. Noise and Information in Nanoelectronics, Sensors and Standards, Santa Fe, New Mexico USA, (218-227). 2-4 June 2003. doi:10.1117/12.500397

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Author Oxtoby, N. P.
Sun, H.
Wiseman, H. M.
Title of paper Noise in detection of qubit states using a quantum point contact
Conference name Noise and Information in Nanoelectronics, Sensors and Standards
Conference location Santa Fe, New Mexico USA
Conference dates 2-4 June 2003
Proceedings title Proceedings of SPIE - The International Society for Optical Engineering   Check publisher's open access policy
Place of Publication United States
Publisher SPIE International Society for Optical Engineering
Publication Year 2003
Sub-type Fully published paper
DOI 10.1117/12.500397
Open Access Status File (Publisher version)
ISSN 0277-786X
Volume 5115
Start page 218
End page 227
Total pages 10
Language eng
Abstract/Summary We present a model for detection of the states of a coupled quantum dots (qubit) by a quantum point contact. Most proposals for measurements of states of quantum systems are idealized. However in a real laboratory the measurements cannot be perfect due to practical devices and circuits. The models using ideal devices are not sufficient for describing the detection information of the states of the quantum systems. Our model therefore includes the extension to a non-ideal measurement device case using an equivalent circuit. We derive a quantum trajectory that describes the stochastic evolution of the state of the system of the qubit and the measuring device. We calculate the noise power spectrum of tunnelling events in an ideal and a non-ideal quantum point contact measurement respectively. We found that, for the strong coupling case it is difficult to obtain information of the quantum processes in the qubit by measurements using a non-ideal quantum point contact. The noise spectra can also be used to estimate the limits of applicability of the ideal model.
Subjects 240401 Optics and Opto-electronic Physics
780102 Physical sciences
Q-Index Code E1
Q-Index Status Provisional Code
Institutional Status UQ
Additional Notes Copyright 2003 Society of Photo-Optical Instrumentation Engineers. One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibited.

Document type: Conference Paper
Collection: School of Physical Sciences Publications
 
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Created: Mon, 27 Aug 2007, 23:05:55 EST