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English

Quantum nondemolition measurement of a kicked qubit

Publication date2005
Abstract

We propose a quantum nondemolition measurement using a kicked two-state system (qubit). By tuning the waiting time between kicks to be the qubit oscillation period, the kicking apparatus performs a nondemolition measurement. While dephasing is unavoidable, the nondemolition measurement can (1) slow relaxation of diagonal density matrix elements, (2) avoid detector back-action, and (3) allow for a large signal-to-noise ratio. Deviations from the ideal behavior are investigated by allowing for detuning of the waiting time, as well as finite-time, noisy pulses. The scheme is illustrated with a double-dot qubit measured by a gate-pulsed quantum point contact.

Keywords
  • Quantum bit
  • Quantum dots
  • Density matrix
  • Matrix elements
  • Signal-to-noise ratio
  • Oscillations
  • Implementation
  • Quantum nondemolition measurement
Citation (ISO format)
JORDAN, Andrew N., BUTTIKER, Markus. Quantum nondemolition measurement of a kicked qubit. In: Physical review. B, Condensed matter and materials physics, 2005, vol. 71, n° 125333, p. 7. doi: 10.1103/PhysRevB.71.125333
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ISSN of the journal1098-0121
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