The University of New South Wales (UNSW) has announced the demonstration of a compact sensor for accessing information stored in the electrons of individual atoms, touted as a breakthrough that brings a scalable quantum computer in silicon one step closer. UNSW is banking on silicon being the key to building the first quantum computer and the results of the research, conducted within the Professor Michelle Simmons-led Simmons group at the Centre of Excellence for Quantum Computation and Communication Technology (CQC2T), show how this may be achieved. Quantum bits (qubits) made from electrons hosted on single atoms in semiconductors is a promising platform for large-scale quantum computers, the university believes, and creating qubits by precisely positioning and encapsulating individual phosphorus atoms within a silicon chip is the approach Simmons' teams are taking. Read also: Australia's ambitious plan to win the quantum race However, adding in all the connections and gates required for scale up of the phosphorus atom architecture was the challenge the researchers were faced with. "To monitor even one qubit, you have to build multiple connections and gates around individual atoms, where there is not a lot of room," Simmons said.