Mitigation of exchange crosstalk in dense quantum dot arrays
Daniel Jirovec (TU Delft - QuTech Advanced Research Centre, Kavli institute of nanoscience Delft, TU Delft - QCD/Vandersypen Lab)
Pablo Cova Fariña (TU Delft - QuTech Advanced Research Centre, Kavli institute of nanoscience Delft, TU Delft - QCD/Vandersypen Lab)
Stefano Reale (TU Delft - QCD/Vandersypen Lab, Kavli institute of nanoscience Delft, TU Delft - QuTech Advanced Research Centre)
Stefan D. Oosterhout (TU Delft - BUS/TNO STAFF, TU Delft - QuTech Advanced Research Centre, Kavli institute of nanoscience Delft, TNO, TU Delft - QN/Kavli Nanolab Delft)
Xin Zhang (TU Delft - QuTech Advanced Research Centre, TU Delft - BUS/Quantum Delft, Kavli institute of nanoscience Delft)
Sander De Snoo (Kavli institute of nanoscience Delft, TU Delft - QCD/Vandersypen Lab, TU Delft - QuTech Advanced Research Centre)
Amir Sammak (TNO, TU Delft - EKL-Users)
Giordano Scappucci (TU Delft - QuTech Advanced Research Centre, Kavli institute of nanoscience Delft, TU Delft - Quantum Circuit Architectures and Technology, TU Delft - QCD/Scappucci Lab)
Menno Veldhorst (Kavli institute of nanoscience Delft, TU Delft - QN/Veldhorst Lab, TU Delft - QuTech Advanced Research Centre, TU Delft - QCD/Veldhorst Lab)
Lieven M.K. Vandersypen (TU Delft - QCD/Vandersypen Lab, TU Delft - QN/Vandersypen Lab, TU Delft - QuTech Advanced Research Centre, Kavli institute of nanoscience Delft)
More Info
expand_more
Other than for strictly personal use, it is not permitted to download, forward or distribute the text or part of it, without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license such as Creative Commons.
Abstract
Coupled spins in semiconductor quantum dots are a versatile platform for quantum computing and simulations of complex many-body phenomena. However, on the path of scale-up, crosstalk from densely packed electrodes poses a severe challenge. While crosstalk onto the quantum dot potentials is nowadays routinely compensated for, crosstalk on the exchange interaction is much more difficult to tackle because it is not always directly measurable. Here we propose and implement a way of characterizing and compensating crosstalk on adjacent exchange interactions by following the singlet-triplet avoided crossing in Ge. We show that we can easily identify the barrier-to-barrier crosstalk element without knowledge of the particular exchange value in a 2×4 quantum dot array. We uncover striking differences among these crosstalk elements that can be linked to the geometry of the device and the barrier gate fan-out. We validate the method by tuning up four-spin Heisenberg chains. The same method should be applicable to longer chains of spins and to other semiconductor platforms in which mixing of the singlet and the lowest-energy triplet is present or can be engineered. Additionally, this procedure is well-suited for automated tuning routines as we obtain a standout feature that can be easily tracked and directly returns the magnitude of the crosstalk.
help_outline