UC Berkeley

This work presents first experimental and theoretical steps towards establishing a novel architecture for quantum information processing (QIP) using trapped electrons in Paul traps. Electrons are attractive for quantum computing because they are extremely light and are natural two-level spin systems (qubit) with a large enough magnetic moment to be manipulated with well-established microwave technology and thermal reservoirs.To that end, we investigate the feasibility for all-electric quantum computing with trapped electron spin qubits. We identify the necessary experimental steps to realize a trapped electron quantum processor through a concrete design proposal, including trapping, cooling, electronic detection, spin readout, and single- and multiqubit gate operations. We numerically study the electron dynamics in linear Paul traps to find the threshold temperature to form two-electron Wigner crystals. We also derive the gate infidelities due to motional errors for trapped electrons and perform numerical simulations that indicate that two-qubit Bell-state fidelities of order 99.99% can be achieved.We design a millimeter-sized PCB Paul trap driven at 1.6 GHz and trap electrons in a room-temperature ultrahigh vacuum setup. Cold electrons are introduced into the trap by photo-ionization of calcium atoms and stay confined for several tens of milliseconds with secular frequencies ranging from several tens to hundreds MHz. We estimate the temperature of trapped electrons through the width of the motional resonance.To demonstrate cooling and electronic detection of the electron motion, we trap electrons in a 4\,K cryostat as the first step and design a cooling and detection circuit. We study the effects of trap anharmonicity and trap voltage fluctuation on the detection signal to identify feasible operating parameters. In addition, we propose to cool the electron motion by bringing its micromotion sideband into resonance with a tank circuit and show that this should yield temperatures lower than what can be achieved with conventional resistive cooling.