Spins in Quantum Solids

This project on Spins in Quantum Solids aims to develop an experimental framework that combines the field of quantum solids with atomic physics and the field of superconducting circuits. We propose to use these quantum solids grown directly on top of superconducting resonators as a host material to trap atoms and couple them to the quantized field of the resonator. Quantum solids, which usually consist of frozen noble gases or in the proposed case solid hydrogen exhibit intersting and counterintuitive properties that are potentially beneficial for these purposes. They are extremely soft and dont exhibit any significant spin-bath. Thus, the host should have little influence on the coherence properties of the trapped atoms, which in turn would lead to long coherence times and a way to design powerful and useful hybrid quantum systems. In order to investigate the system we will start with Rubidium as the implanted impurity as its well known and straightforward level scheme makes it easy to investigate, however, due to the nature of the experiment any atom and/or molecule can be implanted in such a crystal and coupled to the resonator. This gives us great flexibility and will allow us to study different emitters with minimal changes to the experimental setup. The quantum crystals will be grown directly on top of a 2 dimensional superconducting resonator, cooled down much below the freezing point of hydrogen, while at the same time atomic vapour from ovens is implanted during the growth of the crystal. This requires the experiments to be carried out in a cryostat able to reach temperatures cold enough to maintain superconductivity of the resonators as well as thermally polarizing the atoms in their ground state. Thus, the experiment will be carried out in a modified adiabatic demagnization fridge fitted to incorporate the crystal growing and atom deposition procedure, while at the same time offering temperatures well below the freezing point of hydrogen as well as the energy of the microwave transition to be studied. This experiments investigates a completely new regime of hybrid quantum systems and will allow to study new and exciting physics since it allows to greatly reduce complexity and increase modularity of these types of experiments. The flexibility in chosing the impurities in the quantum crystal allows to investigate different types of physics ranging from atoms with potentially high coherence (like alkali metals) to atoms with a higher magnetic moment (like rare earth metals) as well as the rich physics of molecular transitions that can be easily trapped in such a matrix as well.