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Physics Colloquium – “Isotopically Enhanced Triple-Dot Qubits in SiGe”

October 30, 2018 @ 4:00 pm

Andrew Hunter

HRL Laboratories, LLC

Abstract:  Qubits based on silicon offer the promise of low magnetic noise due to isotopic enhancement and the availability of existing silicon growth and fabrication processes. Triple-dot qubits provide exchange-only spin-qubit control, enabling operation using only gate voltages. The main impediments to silicon qubits are charge noise, valley degeneracy, and nuclear magnetism. In this talk, I will summarize our recent results characterizing performance of lithographically defined Si/SiGe triple quantum-dot devices [1, 2], made with isotopically enriched Si to reduce nuclear noise, and operated using symmetric tunnel-barrier control to mitigate the effects of charge noise. I will include average gate error measured through single-qubit randomized benchmarking, a widely used metric for qubit performance, and conclude with a discussion of contributions from known error sources.

  1. Borselli, et al, “Undoped Accumulation-Mode Si/SiGe Quantum Dots, Nanotechnology,” 26, 375202 (2015).
  2. Eng, et al, “Isotopically Enhanced Triple-Quantum-Dot Qubits, Science Advances,” 1, 31500214 (2015).

Berthoud Hall 241


October 30, 2018
4:00 pm
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Berthoud Hall
1516 Illinois St.
Golden, CO 80401 United States
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