Utilizing the spin-orbit interaction of atom qubits, Australian researchers have looked at new ways to scale up qubits, adding a new set of weapons to their arsenal.
Utilizing the spin-orbit interaction of atom qubits, Australian researchers have looked at new ways to scale up qubits, adding a new set of weapons to their arsenal. Spin-orbit coupling, which combines the orbital and spin degrees of freedom in a qubit, enables electric rather than magnetic forces to be used to manipulate the qubit.
Qubits may be spaced wider apart by using the electric dipole interaction between them, giving chip production process flexibility. In one of these methods, which was reported in Science Advances, a group of researchers under the direction of UNSW Professor Sven Rogge looked at the spin-orbit interaction of a silicon boron atom.
According to Professor Rogge, Program Manager at the Centre for Quantum Computation and Communication Technology, “Single boron atoms in silicon are a relatively understudied quantum system, but our research has shown that spin-orbit coupling provides many advantages for scaling up to a large number of qubits in quantum computing” (CQC2T).
Rogge’s group has concentrated on using quick read-out of the spin state (1 or 0) of just two boron atoms in an incredibly tiny circuit, all hosted in a commercial transistor, as a follow-up to earlier work by the UNSW team, published last month in Physical Review X.
“Rapid qubit manipulation and qubit coupling across vast distances are made possible by the efficient electric field coupling of boric atoms in silicon. The possibility of hybrid quantum systems is made possible by the electrical interaction, which also enables connection to other quantum systems “Rogge explains.
Another recent study, this one including phosphorus atom qubits, by Professor Michelle Simmons’ team at UNSW similarly emphasized the significance of spin orbit coupling in atom-based qubits in silicon. The study was just released in the journal npj Quantum Information.
Surprising findings from the research were found. Spin orbit control for silicon electrons was traditionally thought to be poor, leading to spin lifetimes of many seconds, especially for those linked to phosphorus donor qubits. The most recent findings, however, identified a hitherto undetected link of the electron spin to the electric fields normally present in device topologies built using control electrodes.
According to Professor Michelle Simmons, Director of CQC2T, “we found a way to prolong their spin lifetimes to minutes by carefully aligning the external magnetic field with the electric fields in an atomically built device.”
According to Simmons, this recently found coupling of the donor spin with electric fields opens the door for electrically-driven spin resonance methods, which promise great qubit selectivity due to the long spin coherence periods and technical advantages of silicon.
Both findings demonstrate the advantages of comprehending and managing spin orbit coupling for massively parallel quantum computing systems.
Australian silicon quantum computing IP commercialization
Silicon Quantum Computing Pty Limited (SQC), Australia’s first quantum computing company, has been working to develop and market a quantum computer since May 2017 using a variety of intellectual property created at the Australian Centre of Excellence for Quantum Computation and Communication Technology (CQC2T). By 2022, it hopes to have a 10-qubit silicon prototype device ready as a precursor to a large-scale, silicon-based quantum computer.
SQC will continue to collaborate with CQC2T and other members of the Australian and International Quantum Computing ecosystems in order to build and develop a silicon quantum computing industry in Australia and, ultimately, to market its goods and services internationally, in addition to creating its own proprietary technology and intellectual property.