Comment on "Measuring the enhancement factor of the hyperpolarized Xe in nuclear magnetic resonance gyroscopes"

Abstract

Z. Xu, et al. [Phys. Rev. A 103, 023114 (2021)], have reported a measurement for the enhancement factor $\kappa$, which characterizes the overlap of the electron wavefunction with the noble-gas nucleus in Cs-$^{129}$Xe spin-exchange optical pumping (SEOP), that is more than an order of magnitude higher than previous experimental results and theoretical estimates. There is no plausible proposed physical basis for this discrepancy. As the authors repeatedly mischaracterize the nature and properties of the enhancement factor and do not completely describe their experimental technique, there is little reason to accept or consider this result in its current form in the context of future relevant work on Cs-Xe SEOP and its applications.