Simulations of Spin Qubit Dynamics Made Simple*

The coherence of solid-state spin qubits is limited by their magnetic environment, consisting of electron and nuclear spins (see, e.g. [1]). To facilitate and enhance first-principles calculations of qubits’ coherence, we developed PyCCE, an open-source Python library for simulating the dynamics of spin qubits in a spin bath using the cluster-correlation expansion (CCE) method. PyCCE includes modules to generate realistic spin baths, employing coupling parameters computed from first principles with electronic structure codes (see, e.g. [2]), and enables the user to run simulations with either the conventional or generalized CCE method.

We highlight several use cases of the Python library, including: the calculation of the Hahn-echo coherence time of the nitrogen-vacancy in diamond; the calculation of the coherence time of the basal divacancy in silicon carbide at avoided crossings; and the calculation for magnetic field orientation-dependent dynamics of a shallow donor in silicon [3].