Digital Twin Simulations Toolbox of the Nitrogen-Vacancy Center in Diamond

Abstract: Color centers defects in solids, and particularly the nitrogen-vacancy (NV) center in diamond, are crucial physical platforms for quantum technology applications. Therefore, a precise and rigorous numerical modeling of the NV system is indispensable for the continued advancement of the field. Within this context, this work develops a Python software for simulating the NV spin dynamics in pulsed sequences under general experimental conditions, i.e. a digital twin. The library accounts for electromagnetic pulses and other environmental inputs, which are used to solve the system's time-evolution dynamics, resulting in a physical output in the form of a quantum mechanical observable given by the fluorescence. The simulations framework is based on a non-perturbative time-dependent Hamiltonian model, solved in the laboratory frame. Whereby eliminating oversimplifications such as the assumption of instantaneous $\delta$-pulses and rotating wave approximations, our simulations reveal subtle dynamics from the realistic pulse constraints that impact quantum systems. Three use-case examples illustrate the use of the software and validate it by comparing the simulation results with well-established experimental works, relevant to the fields of quantum computing (two-qubit conditional logic gates), sensing (noise resilient dynamical decoupling sequences between NV and couples spins) and networks (teleportation of a quantum state between entangled NVs). Overall, this digital twin delivers a robust and detailed numerical modeling of the NV spin dynamics, with simple and accessible usability, for an extensive application range.