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Spin-based quantum information processing

quantum dot deviceA well-known technology that has long been used in biomedical imaging also serves as a natural test-bed for quantum computing. Nuclear Magnetic Resonance (NMR) manipulates the quantum states of nuclear “spins” in molecules. Because the nuclei behave like tiny magnets, they can be controlled and manipulated using magnetic fields and radiofrequency pulses — and thus serve as qubits. So far, NMR has been the most successful system in implementing quantum algorithms.

Jonathan Baugh and 3 studentsA team of researchers led by faculty at the Institute for Quantum Computing (IQC) Raymond Laflamme and David Cory hold the current record for the most well-characterized qubits harnessed in a single experiment (12).

Jonathan Baugh and his research team

Other IQC faculty including Jonathan Baugh, Joseph Emerson, Debbie Leung, and Michele Mosca have also made numerous critical contributions to the development of spin-based 
quantum computing.   

Future research will require a platform that can be scaled up to harness an increasing number of qubits. Trapping and controlling single electron spins in nanoscale devices (such as point defects, quantum wires or semiconductor quantum dots) is at the heart of research done by IQC researchers Jonathan Baugh and David Cory. Creating a viable system with many qubits is key to realizing the full power of quantum information processing.

Spin-based systems can be used not only as quantum computer prototypes but also as sensors. IQC faculty member David Cory’s research in this area has included the improvement of neutron interferometry, in collaboration with the National Institute of Standards and Technology (NIST) in Maryland. The development of interferometers inspired by quantum error correction techniques has already resulted in greatly enhanced robustness and permitted the design of special purpose NI for new applications to magnetic and soft matter. Quantum actuators currently under development in Cory’s lab include electron spin control of nuclear spins, electron spin control of transport, optical control of electron and nuclear spins, and electron spin control of superconducting circuits.

Ultimately, this research aims to integrate quantum sensors and actuators into more complex systems and achieve higher levels of functionality. These complex systems could be used, for example, to detect single spins or even serve as building blocks for the development of practical quantum information processors.