Two-qubit gates – the central building blocks of quantum computers – operate by exploiting tunnelling interactions between qubits. A team of researchers in Australia has now found a way to optimize these interactions in silicon by determining where the qubits should be positioned within the silicon crystal lattice. The work, which was carried out at the Centre of Excellence for Quantum Computation and Communication Technology (CQC2T) and Silicon Quantum Computing (SQC), is a step forward in the race to scale up silicon-based quantum processors.
Quantum tunnelling occurs when a particle passes through an energy barrier despite not having enough energy (according to classical physics) to overcome it. The phenomenon is at the heart of many modern technologies, including scanning tunnelling microscopy (STM), some types of CMOS electronics and quantum devices in which electrons are confined and manipulated.
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