Hexagonal Boron Nitride Quantum Simulator: Prelude to Spin and Photonic Qubits.

The quest for qubit operation at room temperature is accelerating the field of quantum information science and technology. Solid state quantum defects with spin-optical properties are promising spin- and photonic qubit candidates for room temperature operations. In this regard, a single boron vacancy within hexagonal boron nitride (h-BN) lattice such as defect has coherent quantum interfaces for spin and photonic qubits owing to the large band gap of h-BN (6 eV) that can shield a computational subspace from environmental noise. However, for a defect in h-BN to be a potential quantum simulator, the design and characterization of the Hamiltonian involving mutual interactions of the defect and other degrees of freedom are needed to fully understand the effect of defects on the computational subspace. Here, we studied the key coupling tensors such as zero-field splitting, Zeeman effect, and hyperfine splitting in order to build the Hamiltonian of the defect. These eigenstates are spin triplet states that form a computational subspace. To study the phonon-assisted single photon emission in the defect, the Hamiltonian is characterized by electron-phonon interaction with Jahn-Teller distortions. A theoretical demonstration of how the Hamiltonian is utilized to relate these quantum properties to spin- and photonic-quantum information processing. For selecting promising host 2D materials for spin and photonic qubits, we present a data-mining perspective based on the proposed Hamiltonian engineering of the defect in which h-BN is one of four materials chosen to be room temperature qubit candidates.