High-purity solid parahydrogen for trapping atoms and molecules

Alkali atoms trapped in solid hydrogen matrices have demonstrated ultralong electron spin coherence times and are promising as quantum sensors. Solid hydrogen consists of hydrogen molecules which can exist in two nuclear spin states: I=0 parahydrogen and I=1 orthohydrogen. Prior work has revealed that the spin coherence of atoms (and the nuclear spin coherence of molecules) is limited by magnetic noise from orthohydrogen molecules in the parahydrogen matrix. Through the use of a cryogenic catalyst we purify gaseous parahydrogen prior to deposition and grow solid parahydrogen matrices with lower orthohydrogen impurity fractions than previously reported in the literature. This should lead to greater spin coherence times and improved quantum sensing.