addressing molecular and donor Spins with MIcrowave puLsEs through Superconducting circuits for QUantum Information Processing

This proposal aims at implementing experiments with hybrid spin-superconducting circuits. The targeted breakthrough is the encoding of multifrequency pulses in multilevel spin systems demonstrating basic operations for quantum information processing. To this end, we first plan to develop our experimental setup (heterodyne spectrometer and miniaturized coil-resonators) to generate combined radiofrequency (RF) and microwave (MW) pulses to address the spins. Our original approach includes the use of field resilient YBCO superconducting planar microwave (MW) resonators. We shall focus on ensembles of spin centers of interest and available within NQSTI, such as vanadyl molecular derivatives and phosphorus donors in silicon as building blocks of quantum hardware. We plan to test pulse sequences to manipulate electron and nuclear states of the spin centers. Alternatively, we shall develop and test strategies to control entanglement in coupled spin centers. Experiments can be readily performed at 2K and 0.3K with existing cryostats while we plan the acquisition of a dilution refrigerator as a suitable facility dedicated to these types of experiments. The UNIMORE team proposes an interdisciplinary and synergic approach to the problem that also includes: i) refinement of molecular samples; ii) ab initio calculations of spin decoherence times of P defects in Si/oxide heterostructures; iii) design and testing of cryogenic electronics for the generation of MW/RF pulses.