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arXiv · 2605.19001

Collective charge measurement in quantum dot chains: controlling barrier occupation and tunneling current

Alok Nath Singh·Rafael Sánchez·Andrew N. Jordan
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Abstract

We investigate nonequilibrium transport in a triple-quantum-dot (TQD) system, where the central dot acts as a discrete tunnel barrier, subject to continuous monitoring by a quantum point contact (QPC) that is capacitively coupled to all three dots with independently tunable strengths. We show that this global measurement scheme affects transport in a qualitatively distinct manner from single-site measurement. By engineering structured dephasing, measurement provides a significant improvement in the barrier occupation and tunneling current. In the strong-measurement limit, the steady state becomes independent of the underlying Hamiltonian parameters, and the barrier occupation can approach 1/2 for suitable measurement configurations. We identify an optimal measurement configuration that maximizes the steady-state current and show that near-optimal performance can be achieved with a simple central-dot readout scheme.

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Alok Nath Singh, Rafael Sánchez, Andrew N. Jordan. 2026-05-18. Collective charge measurement in quantum dot chains: controlling barrier occupation and tunneling current. https://arxiv.org/abs/2605.19001

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