Experimental study of hole spin qubits in gated semiconductor devices for quantum processing and communication applications

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It is well established that quantum computers will be significantly more powerful for certain computation and optimization tasks and that single photons used as “flying qubits” will provide 100% security against possible eavesdropping attacks. Solid-state spin qubits attract a rapidly growing worldwide interest for developing quantum information and secure communication applications. An isolated electron spin is the most natural two-level system for a quantum bit or a qubit, the basic element of a quantum computer. Semiconductor based spin qubits form the most promising platform from at least the scalability point of view for building many-qubit quantum processors, because semiconductors can naturally adopt all developments of the advanced microelectronics silicon technology. The vast majority of studies to date have been performed on electron spin qubits in different semiconductor materials. In contrast to more studied electron qubits, this proposal is devoted to exploration of hole spin qubits isolated in gated quantum dot devices. Using hole spin qubits represent a new paradigm for emerging quantum information and communication technologies. The absence of an electron in a fully filled semiconductor valence band, i.e. a hole, can be treated as a positive quasiparticle which can move and possess spin. Holes possess a number of attractive properties for spin qubit applications. Specifically, holes have much stronger spin-orbit coupling, which can be used for much faster spin manipulations, and a reduced hyperfine interaction with surrounding nuclear spins for improved quantum coherence. Additionally, the valence band is inherently free from valleys, which is important to avoid unwanted degeneracies of qubit states. The long term goal of my proposal is the exploration of hole spin qubits as a new system platform for quantum computing and secure communications. In the next five years, my research will focus on developing single- and two-spin hole qubits in gated quantum dot devices. Coherence properties of the hole spin qubits will be studied by different experimental methods such as single-hole electric dipole spin resonance (EDSR), Rabi oscillations and Ramsey fringes. An advanced latching protocol pioneered in our group will be used in studies requiring reliable single-shot read-out of spin qubit states. The fundamental knowledge attained in this research program will be published in open-access journals and can be used by other researches and/or by high-tech companies interested in quantum technologies. There is growing interest in quantum technologies worldwide, including in Canada. Consequently, there is a growing demand for highly qualified personnel (HQP) familiar with quantum physics and technologies. The HQP trained in the course of this research will acquire necessary knowledge and practical skills required in the emerging high-tech job market in Canada.