Since the 1960s, technological advances have enabled silicon transistors to keep shrinking, causing computational capability to grow exponentially. However, transistors cannot shrink much further; they are already so small that the laws of quantum mechanics begin to impair their performance. Fortunately, quantum mechanical behaviour also opens amazing new possibilities for computation. A well-developed theory for a radically new Quantum Information Technology proves that computers that rely fundamentally on quantum mechanics can potentially solve many important computational problems that will remain forever intractable using conventional computers. This will impact fields as diverse as drug development, design and discovery of new materials, machine learning, and cryptography.
We are working to build quantum technologies using silicon, the very same material currently used to make transistors and computer chips for the giant ‘classical’ computing industry. Very fortunately, silicon also hosts arguably the best quantum bits (‘qubits’) in the industry. We are particularly excited about an opportunity to link the excellent spin qubits associated with chalcogen donors (namely selenium, sulphur, and tellurium) in silicon with photon qubits. Much of our current work concerns the development and proof of principle of this ‘photonic link’ in silicon. Not only will photonic qubits enable links between various spin qubits, they also can be used to link multiple quantum chips — towards what some call a ‘quantum internet’. This approach will also have concrete scale-up advantages including higher-temperature operation, ease of manufacturing, and robust and atomically identical qubits. If we’re successful, this platform will be used not only to make a quantum computer but also to make provably secure quantum communication, quantum sensors, and more.