Theoretical study on nonequilibrium dynamics of electrons in mesoscopic systems

Abstract

Generating single-electrons and controlling of individual single-electrons in mesoscopic systems are important to explore the electron version of quantum optics. Moreover, a precise control of the Coulomb interaction between generated electrons is required to study nonlinear regime in electron quantum optics where the presence of an electron changes a quantum state of another electron. This nonlinearity is applicable for the quantum logic gates based on electron flying qubits. For realizations of these applications, there are several requirements to be done. It is required to have a phase coherent single-electron that can interact with another electron via the Coulomb interaction. Measuring a wave function probability with respect to time (arrival time distribution) is needed to evaluate the wave function and to find the timing for electron collisions. Understanding dynamics of two electrons with Coulomb interaction is important for the nonlinearity. In this dissertation, we present studies pursuing the above requirements. Firstly, we demonstrate a new single-electron source having hybrid structures of a coherent single-electron source and a single-electron source that emits electrons interacting with other electrons. Secondly, we study the quantum dynamics of generated single-electrons through a dynamical potential barrier and quantify the condition at which the barrier reconstructs the arrival time distribution of electrons. Thirdly, we study time-resolved dynamics of electrons with the Coulomb interaction, by colliding two counter-propagating electrons. Lastly, we suggest a way to quantify and sense the Coulomb interaction.