We propose two platforms for realizing macroscopic qubits in spintronics devices. The first prototype magnetic quantum information processing device, based on spin superfluidity and spin Hall phenomena, realizes the spin-supercurrent analog of the superconducting phase qubit, and allows for full electrical control and readout. The second device stores a quantum state in a topological defect of a magnetic insulator and realizes the magnetic analog of the three-level rf-SQUID qubit. We propose non-invasive methods to coherently control and readout the quantum state using ac magnetic fields and magnetic force microscopy, respectively. Various physical estimates for both devices, e.g., operational temperatures and decoherence times, will be made and discussed.
Professor Takei completed the B.Sc. program in Physics and Mathematics at the University of British Columbia in 2003. He then completed his Ph.D. in Physics at University of Toronto in 2008 under the supervision of Prof. Yong Baek Kim. After that, he spend time as a postdoctoral scholar in Stuttgart, Maryland (with Prof. S. DasSarma), and at UCLA (with Yaroslav Tserkovnyak) before he joined CUNY in 2014. His interests lie broadly in the theory of quantum transport and non-equilibrium phenomena in nanostructures and quantum phase transitions, quantum and classical spintronics, with various applications in classical and quantum information.