(PhysicsWorld) Individual atoms on a surface can be used as quantum bits (qubits) for quantum computing applications. That is the claim of scientists at IBM Research who have shown that they can control the positions of each qubit with atomic precision by manipulating the atoms in a scanning tunnelling microscope (STM). Controlling the position of these qubits also allows the team to modify interactions between pairs of atoms.
“This work is an important step towards using spins on a surface as qubits for quantum computing,” team member said. “The STM allows us to build essentially arbitrary structures of such atoms, which makes it possible for us to control how strongly they will interact with each other.”
Since these single-atom qubits are highly sensitive to magnetic fields, they might also be used as quantum sensors to measure the weak magnetism or electric fields of nearby atoms, say the researchers.
The team, which includes researchers from the Center for Quantum Nanoscience at the Institute for Basic Science (IBS) and Ewha Womans University, both in Seoul in Korea, and the Clarendon Laboratory at the University of Oxford in the UK, now plans to optimize the local environment of the atomic qubits to improve their quantum coherence time. “For example, we will try different surfaces and types of magnetic atoms,” says Lutz. “We would also like to design and build atomic structures containing more magnetic atoms to explore quantum entanglement for quantum simulations.”

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