Ohio State researchers are among the scientific leaders that have just been awarded a total of $218 million in funding from the Department of Energy (DOE) in the important emerging field of Quantum Information Science (QIS). The awards were made in conjunction with the White House Summit on Advancing American Leadership in QIS, highlighting the high priority that the Administration places on advancing this multidisciplinary area of research, which is expected to lay the foundation for the next generation of computing and information processing as well as an array of other innovative technologies. The Ohio State effort is led by Prof. Ezekiel Johnston-Halperin, Department of Physics, and joins a team led by Prof. Greg Fuchs (Applied Physics, Cornell), along with Profs. Dan Ralph (Physics, Cornell) and Michael Flatté (Physics, University of Iowa). The full announcement from DOE can be found here.
The contributions of the Ohio State team center around their ability to grow thin films of an organic-based magnetic material that has the potential to play a major role in the emerging area of “hybrid quantum interfaces.” Recent news accounts have documented the exciting progress being made in the development of individual quantum bits (qubits) and their combination into simple quantum circuits, with major advances being reported by both academic researchers and industry (for example, IBM, Google, and D-Wave). However, the full power of QIS will come from having these individual quantum processors linked to other quantum sensors and distributed quantum networks. In analogy with classical computers, this challenge is similar to linking the CPU of an iPhone to a built-in accelerometer to detect motion and position, or using local networks to link the individual computers in a data center to provide the increased computing power that underlies the current revolution in “big data.”
The thin films developed by Prof. Johnston-Halperin’s research group are composed of organic molecules bonded to vanadium metal atoms, a material known as vanadium tetracyanoethylene (V[TCNE]2), and are notable for the extremely high quality of their magnetic excitations. In the same way that a tuning fork will emit a pure tone when you hit it with your hand, magnetic materials will “ring” when hit with a pulsed magnetic field and the purity of the tone (ringing at only one frequency) and the lifetime of the ringing (how long until it goes quiet) measure the quality of the material. The essence of the team proposal is to exploit this ringing as a “quantum bus” to transfer information from one quantum system to another. For example, such a bus could couple a superconducting qubit (such as those being developed by the companies listed above) to an optical qubit that can exchange quantum information across the same optical fiber network that forms the backbone of modern telecommunications and networking. Following this analogy, the materials produced by Ohio State have demonstrated a purity of tone that is unprecedented, opening the door to the development of new QIS devices and hybrid quantum networks wherein individual quantum devices are optimized for functions such as computing, sensing, and communication and coordinated through the magnetic excitations in V[TCNE]2.