The team of researchers at the University of Maryland, Harvard University, and Purdue University aims to develop flexible methods to store and manipulate information in quantum bits (qubits), to achieve a more robust and efficient quantum computer. The researchers will apply a magnetic field to a "topological superconductor" - a material in which electrons can form unusual pairs at low temperature. The researchers will use fine control of the magnetic field to create and exchange quantum whirls of electrical current, called vortices, whose distinct patterns and trajectories encode quantum information. An important component of this program will be the development of large-scale classical computing tools to predict the motion of individual electrons and vortices, to streamline the efficiency of more costly experimental operations. The software tools will be publicly available at nanoHUB.org, an open-access website that reaches over 1.4 million visitors annually. Collectively, the team of four senior researchers will advise and educate four graduate students and eight undergraduates, with a strong focus on recruiting new students to physics through well-mentored summer research programs, and on providing opportunities for collaborative student exchanges between the three universities.
Topological quantum computing has been aggressively pursued by industries, national laboratories, and universities worldwide in the last decade. The active strategy universally relies on the realization and transport of Majorana fermions along 1D nanowires - with demanding requirements for atomically-precise interfaces, ultra-low temperature, and carefully-tuned magnetic field. The team of researchers will pursue a disruptive new approach using a magnetic force microscope tip to manipulate Majorana fermions in the vortex cores of bulk topological superconductors and Josephson junctions, and to read out their quantum state. Potential advantages include larger B-field and temperature range, robustness to disorder, and a continuous two-dimensional space in which to explore and control Majorana interactions, orthogonal to predefined wires. The team will (a) propose devices and readout mechanisms for braiding Majorana bound states superconducting vortex cores; (b) conduct atomic scale simulations of quantum transport in these systems; (c) synthesize the topological superconductor Fe(Se,Te) using molecular beam epitaxy; (d) use scanning tunneling microscopy to identify Majorana zero modes; (e) use magnetic force microscopy to manipulate vortices and braid their Majorana bound states; and (f) fabricate and read transport-based devices to realize prototype topological qubits.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
