Study of dipole moments of LiSr and KRb molecules by quantum Monte Carlo methods

TL;DR

This study employs advanced quantum Monte Carlo methods to accurately compute the electric dipole moments of LiSr and KRb molecules, providing insights into their potential for ultracold quantum applications.

Contribution

It introduces a fully-correlated quantum Monte Carlo approach for precise dipole moment calculations of heteronuclear dimers, surpassing traditional methods in accuracy.

Findings

LiSr exhibits a highly nonlinear dipole moment curve.

Quantum Monte Carlo results highlight the importance of many-body correlations.

Potential for dipole moment tunability through vibrational state control.

Abstract

Heteronuclear dimers are of significant interest to experiments seeking to exploit ultracold polar molecules in a number of novel ways including precision measurement, quantum computing, and quantum simulation. We calculate highly accurate Born-Oppenheimer total energies and electric dipole moments as a function of internuclear separation for two such dimers, LiSr and KRb. We apply fully-correlated, high-accuracy quantum Monte Carlo methods for evaluating these molecular properties in a many-body framework. We use small-core effective potentials combined with multi-reference Slater-Jastrow trial wave functions to provide accurate nodes for the fixed-node diffusion Monte Carlo method. For reference and comparison, we calculate the same properties with Hartree-Fock and with restricted Configuration Interaction methods, and carefully assess the impact of the recovered many-body correlations on the calculated quantities. For LiSr we find a highly nonlinear dipole moment curve, which may make this molecule's dipole moment tunable through vibrational state control.