Grant: Research Tools and Instruments - Category 1 (<$150,000)

Building a quantum computer is one of the great scientific and engineering challenges of our time. A quantum processor stores and manipulates an amount of information that is exponential in the number of elementary bits, in contrast to classical information processing which is linear in the bit number. A quantum computer represents the most general type of information processor allowed by the known laws of physics, and it has been proven that a quantum computer can solve certain problems that are classically intractable. Efforts to build quantum processors are bolstered by the theoretical results of quantum fault tolerance, which prove that, in principle, decoherence of quantum states is not a fundamental obstacle to quantum computing as long as the error rate is below a threshold. To build such a device, we need building blocks that are capable of performing universal quantum logic operations, can maintain coherent quantum states over a large number of operations, and can be efficiently integrated into a large-scale architecture. Just as solid-state (semiconductor) technology has allowed modern classical information processors to reach incredible speeds and information densities, appropriately designed solid-state quantum devices will provide a scalable, practical solution for realizing quantum processors. Our approach encodes quantum information in the spin of individual electrons confined in mesoscopic devices called quantum dots. The intrinsic physics of our devices allows single spins to be manipulated with much higher speed and fidelity than has previously been demonstrated. We aim to show, for the first time, universal quantum logic in a scalable multi-qubit system in which both one- and two-qubit operations can be carried out on a timescale of nanoseconds. Fast gate operations will be crucially important for overcoming decoherence and for performing large-scale quantum computations in future devices. This Research Tools and Instruments Grant will fund a set of electronics instrumentation that will work together with existing infrastructure and devices to enable fast quantum logic.