5 research outputs found
Real-time counting of single electron tunneling through a T-shaped double quantum dot system
Real-time detection of single electron tunneling through a T-shaped double
quantum dot is simulated, based on a Monte Carlo scheme. The double dot is
embedded in a dissipative environment and the presence of electrons on the
double dot is detected with a nearby quantum point contact. We demonstrate
directly the bunching behavior in electron transport, which leads eventually to
a super-Poissonian noise. Particularly, in the context of full counting
statistics, we investigate the essential difference between the dephasing
mechanisms induced by the quantum point contact detection and the coupling to
the external phonon bath. A number of intriguing noise features associated with
various transport mechanisms are revealed.Comment: 8 pages, 5 figure
Quantum measurement characteristics of double-dot single electron transistor
Owing to a few unique advantages, double-dot single electron transistor has
been proposed as an alternative detector for charge states. In this work, we
present a further study for its signal-to-noise property, based on a full
analysis of the setup configuration symmetry. It is found that the
effectiveness of the double-dot detector can approach that of an ideal
detector, if the symmetric capacitive coupling is taken into account. The
quantum measurement efficiency is also analyzed, by comparing the measurement
time with the measurement-induced dephasing time.Comment: 7 pages, 5 figure
Calculation of the current noise spectrum in mesoscopic transport: A quantum master equation approach
Based on our recent work on quantum transport [X. Q. Li , Phys. Rev. B 71, 205304 (2005)], we show how an efficient calculation can be performed for the current noise spectrum. Compared to the classical rate equation or the quantum trajectory method, the proposed approach is capable of tackling both the many-body Coulomb interaction and quantum coherence on an equal footing. The practical applications are illustrated by transport through quantum dots. We find that this alternative approach is in a certain sense simpler and more straightforward than the well-known Landauer-Buttiker scattering matrix theory