Non-resonant quantum logic gates

The most common realization of quantum logic gates and control is based on Rabi oscillations, which cause a periodic resonant excitation of the system. It has certain limitations and complications, like counter-rotating terms. We study an alternative approach for implementing quantum logic gates based on Landau-Zener-Stückelberg-Majorana (LZSM) interferometry with non-resonant driving and the alternation of adiabatic evolution and non-adiabatic transitions. Compared to the Rabi oscillations method, the main differences are a non-resonant excitation frequency and a small number of periods in the external excitation. One of the goals is to achieve a higher speed of qubit operations without losing fidelity. Both of these characteristics have major importance for experimental realizations of quantum computers. We study different aspects of non-resonant excitations: qubit dynamics, relaxation, coupling with the environment, and optimizing the speed of gates by increasing the number of periods in the external excitation. We explore related mechanisms and dynamics for single and two-qubit gates. The parameters of the external excitation required for implementing some specific gate are defined using the adiabatic-impulse model approach. This mechanism can be applied for a large variety of multi-level quantum systems and external excitations, providing a method for implementing qubit logic gates on them.