Detuning modulated universal composite gates.

Technologies which harness the laws of quantum mechanics in computational science are pushing toward exponential improvement of information processing tasks. This, as well as innovative functionalities in sensing and imaging, break the fundamental classical limits of computation and measurement. Yet, quantum computation and quantum information processing (QIP) rely on the accuracy of unitary gate operations. In all quantum systems, unitary gates are highly sensitive to deviations from the target control parameters due in part to fabrication errors and environmental changes. Thus, translating quantum information schemes from abstraction to realistic conditions requires robust designs to overcome inherent errors. Moreover, such gates must be universal, meaning that they are independent of the initial state of the qubit system. This adds to the complexity of implementing precise unitary gates that are required for scalable quantum computation. Herein, detuning-modulated composite pulses (DMCPs) are a promising method for achieving accurate and robust state transfer in any qubit hardware platform. We present a DMCP scheme to achieve such universal quantum gates well within the error threshold suitable for QIP. Universal DMCPs are a compelling mechanism for realizing unitary gates in quantum computers under error-prone experimental conditions. These pulses are robust to inaccuracies in pulse strength, duration, resonance offset errors, Stark shifts, etc. within the lifetime of the system.