Phys.org November 13, 2024
The coherent control of interacting spins in semiconductor quantum dots is of interest for quantum information processing and studying quantum magnetism from the bottom up. Researchers in the Netherlands demonstrated a 2 × 4 germanium quantum dot array with full and controllable interactions between nearest-neighbour spins. As a demonstration of the level of control, they defined four singlet–triplet qubits in this system and showed two-axis single-qubit control of each qubit and SWAP-style two-qubit gates between all neighbouring qubit pairs, yielding average single-qubit gate and Bell state fidelities. Combining these operations, they implemented a circuit designed to generate and distribute entanglement across the array and achieved a fidelity of 75(2)% and a concurrence of 22(4)%. According to the researchers their results highlight the potential of singlet–triplet qubits as a competing platform for quantum computing and indicate that scaling up the control of quantum dot spins in extended bilinear arrays can be feasible… read more. Open Access TECHNICAL ARTICLE
Device and energy spectroscopy. Credit: Nature Nanotechnology, 31 October 2024