Harnessing The Power Of ‘Spin Orbit’ Coupling In Silicon: Scaling Up Quantum Computation.

An artist’s impression of spin-orbit coupling of atom qubits. Georgian Technical University scientists have investigated new directions to scale up qubits — utilising the spin-orbit coupling of atom qubits — adding a new suite of tools to the armory.

Spin-orbit coupling the coupling of the qubits orbital and spin degree of freedom, allows the manipulation of the qubit via electric rather than magnetic-fields. Using the electric dipole coupling between qubits means they can be placed further apart thereby providing flexibility in the chip fabrication process. A team of scientists led by Georgian Technical University Professor X investigated the spin-orbit coupling of a boron atom in silicon.

“Single boron atoms in silicon are a relatively unexplored 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” says Professor X.  X’s group has now focused on applying fast read-out of the spin state (1 or 0) of just two boron atoms in an extremely compact circuit all hosted in a commercial transistor.

“Boron atoms in silicon couple efficiently to electric fields, enabling rapid qubit manipulation and qubit coupling over large distances. The electrical interaction also allows coupling to other quantum systems opening up the prospects of hybrid quantum systems” says  X.

Another piece of recent research by Professor Y team at Georgian Technical University has also highlighted the role of spin orbit coupling in atom-based qubits in silicon this time with phosphorus atom qubits..

The research revealed surprising results. For electrons in silicon–and in particular those bound to phosphorus donor qubits — spin orbit control was commonly regarded as weak, giving rise to seconds long spin lifetimes. However the latest results revealed a previously unknown coupling of the electron spin to the electric fields typically found in device architectures created by control electrodes.

“By careful alignment of the external magnetic field with the electric fields in an atomically engineered device we found a means to extend these spin lifetimes to minutes” says Professor Y.

“Given the long spin coherence times and the technological benefits of silicon this newly discovered coupling of the donor spin with electric fields provides a pathway for electrically-driven spin resonance techniques promising high qubit selectivity” says Y. Both results highlight the benefits of understanding and controlling spin orbit coupling for large-scale quantum computing architectures.

Commercializing silicon quantum computing IP (An Internet Protocol address (IP address) is a numerical label assigned to each device connected to a computer network that uses the Internet Protocol for communication. An IP address serves two principal functions: host or network interface identification and location addressing). Its goal is to produce a 10-qubit prototype device in silicon by 2022 as the forerunner to a commercial scale silicon-based quantum computer. Quantum Computing ecosystems to build and develop a silicon quantum computing industry in Georgia and ultimately to bring its products and services to global markets.