Coherent manipulation of three-spin states in a Si/SiGe triple quantum dot

Quantum dot arrays provide a promising platform for quantum information processing. In Si-based devices, recent technological advances make it possible to implement single- and two-qubit operations with high fidelities. A three-qubit system is a next step toward scaling up and it is particularly important for realizing a quantum error-correcting code. In this work, we demonstrate coherent manipulation of three individual spins in a Si/SiGe triple quantum dot by site-selective electric dipole spin resonance. Spins in the left and right dots are read out by a spin-selective tunneling technique while the center spin is measured by reading out the left spin subsequently to a controlled-rotation operation. We also report our recent progress on controlled-controlled-rotation where the resonance frequency of the center spin depends on both left and right spin states.

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