A relativistic ab initio study of P,T-odd effects in the laser coolable SrOH molecule

Ultracold polyatomic molecules are of great importance in fundamental physics and quantum information science. As progress toward precision measurements with the ultracold SrOH molecule is currently underway [Phys. Rev. Lett. 134, 083401 (2025)], we present a four-component relativistic ab initio study of various parity (P)-and time-reversal (T)-violating (P,T-odd) interactions in this molecule in its ground electronic state. Two analytic techniques, viz. the Zvector (energy-derivative) method and the expectation-value approach, within the relativistic singlereference coupled-cluster framework are employed to determine the P,T-odd molecular sensitivity parameters, which are essential for the design of precision experiments with SrOH and for the analysis of their results. We find that the P,T-odd parameters of SrOH are nearly equal to those of its isoelectronic diatomic molecule, SrF; however, owing to the enhanced rejection of systematic errors enabled by polyatomic molecules, SrOH emerges as a more promising candidate for precision measurements.