Controlling relaxation of nuclear spin qubit ensembles for a more sensitive search for axion-like dark matter

Cosmic Axion Spin Precession Experiment (CASPEr) is a laboratory scale experiment searching for ultralight axion-like dark matter, using nuclear magnetic resonance [D. Budker, P. W. Graham, M. Ledbetter, S. Rajendran, A. O. Sushkov, Phys. Rev. X, 4,021030 (2014)]. I will describe our work on the next phase of the experiment, with the goal of searching in the kHz – MHz frequency band, using SQUID sensors. I will also describe our study of transient light-induced paramagnetic centers in ferroelectric PMN-PT ($\mathrm{(PbMg_{1/3}Nb_{2/3}O_3)_{2/3} - (PbTiO_3)_{1/3}}$) crystals. We use these paramagnetic centers to control the polarization and relaxation of the nuclear spin qubit ensemble, allowing us to improve sensitivity to axion-like dark matter.