Multiple Pathways Enhance Quantum Computing


Researchers from Centre for Quantum Computation & Communication Technology explored multiple pathways to enhance atom-based computing architectures using spin-orbit coupling

A team of researchers from Centre for Quantum Computation & Communication Technology (CQC2T) studied new directions to enhance qubits. Spin-orbit coupling, the coupling of the qubits’ orbital, and spin degree of freedom, enables the manipulation of the qubit through electric instead of magnetic-fields. Use of electric dipole coupling between qubits suggests that qubits can be placed further apart to offer flexibility in the chip fabrication process. The research was published in the journal Science Advances on December 7, 2018.

In one such approach a team of researchers led by University of New South Wales (UNSW) Professor Sven Rogge studied spin-orbit coupling of a boron atom in silicon. According Professor Rogge, Program Manager at CQC2T, single boron atoms in silicon are a relatively unexplored quantum system, however, the research demonstrated that spin-orbit coupling offers several advantages for enhancing to a large number of qubits in quantum computing. The current research followed the earlier results from the UNSW team that were published in November in the journal Physical Review X. In the current research, the team was focused on applying fast read-out of the spin state (1 or 0) of just two boron atoms in a highly compact circuit that was hosted in a commercial transistor.

Rogge stated that boron atoms in silicon couple efficiently to electric fields to allow rapid qubit manipulation and qubit coupling over large distances. He also added that the electrical interaction enables coupling to other quantum systems. In a separate research, Professor Michelle Simmons’ team at UNSW highlighted the role of spin orbit coupling in atom-based qubits in silicon using phosphorus atom qubits. The study reported that spin orbit control was commonly regarded as weak for electrons in silicon and in particular those bound to phosphorus donor qubits. This gives leads to seconds long spin lifetimes. In the current research, the team revealed a previously unidentified coupling of the electron spin to the electric fields that is generally found in device architectures created by control electrodes.