Pulse sequences for controlled 2- and 3-qubit gates in a hybrid quantum register

TL;DR

This paper introduces a quantum control scheme combining resonant pulses and free precession to implement faster 2- and 3-qubit gates in hybrid quantum registers, reducing relaxation effects.

Contribution

It presents a novel control method for hybrid quantum registers that improves gate speed and fidelity by integrating resonant excitation with free precession periods.

Findings

Successfully implemented controlled-NOT gates on NV center spins

Reduced operation time compared to previous methods

Demonstrated population transfer and Rabi oscillations measurement

Abstract

We propose and demonstrate a quantum control scheme for hybrid quantum registers that can reduce the operation time, and therefore the effects of relaxation, compared to existing implementations. It combines resonant excitation pulses with periods of free precession under the internal Hamiltonian of the qubit system. We use this scheme to implement quantum gates like controlled-NOT operations on electronic and nuclear spins of the nitrogen-vacancy center in diamond. As a specific application, we transfer population between electronic and nuclear spin qubits and use it to measure the Rabi oscillations of a nuclear spin in a system with multiple coupled spins.