A Modeling Study on Performance of a CNOT Gate Devices based on Electrode-driven Si DQD Structures

Behaviors of quantum bits (qubits) encoded to electron spins in silicon double quantum dot (Si DQD) systems are examined with a multi-scale modeling approach that combines electronic structure simulations and Thoas-Fermi calculations. Covering the full-stack functionality of Si DQD devices from electrode-driven charge controls to logic operations, we investigate the sensitivity of exchange interaction between two initialized qubits and its effect on the fidelity of controlled-NOT gate operations to understand the experimental reported feature. This preliminary work not only presents a theoretical clue for understanding the major control factors for the gate fidelity, but opens the possibility for further exploration of the engineering details of qubit logic gate devices that is hard to be uncovered with experiments due to the time and the expense.