Quantum-efficient charge detection using a single-electron transistor
Physics and Astronomy, SUNY at Stony Brook - NY, USA
Corresponding author: email@example.com
Accepted: 4 March 2002
We evaluate the detector nonideality (and energy sensitivity) of a normal-state single-electron transistor in the cotunneling regime in a two-charge-state approximation. The (symmetrized) current-charge cross-correlation vanishes for low frequencies, causing two different definitions of detector nonideality to agree. The result, a universal one-parameter function, shows that near-ideal, quantum-limited measurement of a charge qubit is possible for a wide range of small bias voltages. However, near the threshold voltage for crossover to sequential tunneling, the device becomes strongly nonideal. Interpretations of these findings are discussed.
PACS: 73.23.Hk – Coulomb blockade; single-electron tunneling / 03.67.-a – Quantum information / 05.40.-a – Fluctuation phenomena, random processes, noise, and Brownian motion
© EDP Sciences, 2002