Fast spin exchange across a multielectron mediator

• DOI: 10.1038/s41467-019-09194-x
• Publication Date: 2019-03-13T11:02:46Z
• Authors: Filip K. Malinowski; Frederico Martins; Thomas B. Smith; Stephen D. Bartlett; Andrew C. Doherty; Peter D. Nissen; Saeed Fallahi; Geoffrey C. Gardner; Michael J. Manfra; Charles M. Marcus; Ferdinand Kuemmeth
• Keywords: Dynamical decoupling; Exchange interaction

The Heisenberg exchange interaction between neighboring quantum dots allows precise voltage control over spin dynamics, due to the ability precisely overlap of orbital wavefunctions by gate electrodes. This study fundamental electronic phenomena and finds applications in information processing. Although spin-based circuits based on short-range interactions are possible, development scalable, longer-range coupling schemes constitutes a critical challenge within spin-qubit community. Approaches capacitative cavity-mediated effectively couple qubits charge degree freedom, making them susceptible electrically-induced decoherence. alternative is extend range means mediator. Here, we show that multielectron dot with 50-100 electrons serves as an excellent mediator, preserving speed coherence resulting spin-spin while providing several functionalities practical importance. These include (mediated two-qubit rates up gigahertz), distance (of order micrometer), control, possibility sweet spot operation (reducing susceptibility noise), reversal sign (useful for dynamical decoupling from noise).