OH hyperfine ground state: From precision measurement to molecular qubits

We perform precision microwave spectroscopy---aided by Stark deceleration---to reveal the low-magnetic-field behavior of OH in its ²Π3∕2 rovibronic ground state, identifying two field-insensitive hyperfine transitions suitable as qubits and determining a differential Land\'e g factor of 1.267(5)×10^-3 between opposite-parity components of the Λ doublet. The data are successfully modeled with an effective hyperfine Zeeman Hamiltonian, which we use to make a tenfold improvement of the magnetically sensitive, astrophysically important ΔF=±1 satellite-line frequencies, yielding 10.2em0ex7200.2em0ex5290.2em0ex887(10)0.3em0exHz and 10.2em0ex6120.2em0ex2300.2em0ex825(15)0.3em0exHz.