Long-range transport in asymmetric quadruple quantum dot configurations

Abstract Quantum dot arrays are a versatile platform for investigating coherent charge and spin transport, with direct relevance for scalable quantum information processing. While long-range tunneling has been extensively studied in triple quantum dots, the role of reduced symmetry in quadruple quantum dot (QQD) systems remains largely unexplored. Here we show, employing a master equation approach, that coherent long-range charge transfer can persist in QQDs even under reduced symmetry configurations. We identify clear resonance conditions characterized by strongly suppressed population of the intermediate dots, as well as distinctive signatures such as interference between competing long-range channels and current blockade effects. Our results, obtained with experimentally realistic parameters, establish that efficient long-range transfer does not require perfect symmetry, and provide theoretical guidance for future experimental efforts to harness coherent transport in extended quantum dot arrays for quantum technologies.