Strategies for Enhancing Spin-Shuttling Fidelities in Si / Si Ge Quantum Wells with Random-Alloy Disorder

• DOI: 10.1103/prxquantum.5.040322
• Publication Date: 2024-11-08T15:01:48Z
• Authors: Merritt P. Losert; Max Oberländer; Julian D. Teske; Mats Volmer; Lars R. Schreiber; Hendrik Bluhm; S.N. Coppersmith; Mark Friesen
• Keywords: 0301 basic medicine; 03 medical and health sciences

Coherent coupling between distant qubits is needed for many scalable quantum computing schemes. In dot systems, one proposal long-distance to coherently transfer electron spins across a chip in moving potential. Here, we use simulations study challenges spin shuttling <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"><a:mi>Si</a:mi></a:math>/<d:math xmlns:d="http://www.w3.org/1998/Math/MathML" overflow="scroll"><d:mi>Si</d:mi></d:math><g:math xmlns:g="http://www.w3.org/1998/Math/MathML" overflow="scroll"><g:mi>Ge</g:mi></g:math> heterostructures caused by the valley degree of freedom. We show that devices with splitting dominated alloy disorder, can expect encounter pockets low splitting, given long-enough path. At such locations, intervalley tunneling leads dephasing wave function, substantially reducing fidelity. how mitigate this problem modifying heterostructure composition, or varying vertical electric field, velocity, shape and size dot, further combinations these strategies reduce infidelity several orders magnitude, putting fidelities sufficient error correction within reach. Published American Physical Society 2024