Science Daily January 27, 2023 Optically active semiconductor quantum dots have unparalleled photonic properties, but also modest spin coherence limited by their resident nuclei. The nuclear inhomogeneity has thus far bound all dynamical decoupling measurements to a few microseconds. An international team of researchers (UK, Austria) eliminated the inhomogeneity using lattice-matched GaAs–AlGaAs quantum dot devices and demonstrated dynamical decoupling of the electron spin qubit beyond 0.113(3) ms. Leveraging the 99.30(5)% visibility of our optical π-pulse gates, we use up to Nπ = 81 decoupling pulses and find a coherence times hundreds of microseconds. This scaling manifests an ideal refocusing of strong interactions between the electron and the […]
Tag Archives: Semiconductor quantum dots
Study achieves the coherent manipulation of electron spins in silicon
Phys.org January 26, 2023 Electron spins in silicon quantum dots are excellent qubits because they have long coherence times and high gate fidelities, and compatible with advanced semiconductor manufacturing techniques. A team of researchers in the US (University of Rochester, industry) has shown that spin–valley coupling in Si, which drives transitions between states with different spin and valley quantum numbers, enables coherent control of single- and multi-electron spin states without oscillating electromagnetic fields. They demonstrated Rabi oscillations between effective single-spin states in a Si/SiGe double quantum dot that are driven by spin–valley coupling. Together with the exchange coupling between neighbouring electrons, […]