Single-electron transistor architectures for charge motion detection in solid-statequantum computer devices

Abstract

Single-spin detection will be crucial for solid-state quantum computer (QC)architectures in which information is encoded in the spin state of single nuclear orelectron spins. The formidable problem of single-spin detection in a solidcan be mapped to a more tractable problem of single-charge detectionthrough spin-dependent electron transfer which may be observed usingultrasensitive solid-state nanostructure electrometers. Here we describe a read-outarchitecture using single-electron transistors (SETs) that can detect thecharge state of two coupled metal dots, which simulates charge transferin a two-quantum-bit (qubit) spin system. This twin-SET architectureallows significant reduction of random charge noise by correlating twodetector outputs, reducing the probability of read-out errors in the QC.