Quantum measurement characteristics of double-dot single electron transistor

TL;DR

This paper analyzes the quantum measurement properties of a double-dot single electron transistor, highlighting its potential as an effective charge detector with near-ideal efficiency when symmetric coupling is used.

Contribution

The study provides a detailed analysis of the signal-to-noise ratio and measurement efficiency of the double-dot transistor, emphasizing the importance of symmetric capacitive coupling.

Findings

Effectiveness approaches that of an ideal detector with symmetric coupling

Quantum measurement efficiency depends on measurement time and dephasing time

Symmetric configuration enhances detector performance

Abstract

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.