(QuTech.nl) One of the key challenges in building the much coveted and very powerful quantum computer is the building of qubits (quantum bits) that can be scaled to large numbers. Using only standard semiconductor manufacturing techniques, researchers from QuTech have now demonstrated that a single hole, trapped in a germanium quantum dot, can be effectively used as a qubit. Their work was published in Nature Communications on July 10.
A hole is not a real particle but rather a quasi-particle. It does, however, have favourable properties that could make could make it an excellent building block for a quantum computer. Single holes can maintain their quantum state for a long enough period of time to allow quantum computations. They can also be manipulated using electrical signals only, thereby limiting the need for external components to control them and allowing easier upscaling. These properties were predicted already in 2005 but until now it had not been possible to isolate a single hole and use it as a qubit. The group of Menno Veldhorst at QuTech – a collaboration between TU Delft and TNO – have now achieved this feat.
The current results are the culmination of a series of breakthroughs in quantum computing the group of Veldhorst achieved using germanium. Earlier this year, and also in Nature, they published on the first realisation of two-qubit logic with germanium. They are now working on building larger qubit arrays made out of holes in germanium, bringing scalable qubit systems, and therefore the quantum computer, ever closer.

NOTE: QuTech is Co-Producer with 3DR Holdings of the upcoming Inside Quantum Technology Europe event, October 26-30.

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