Spin squeezing an ultracold molecule

TL;DR

This paper proposes a method to achieve spin squeezing in ultracold polar molecules, specifically OH, using static electric and magnetic fields to realize different Hamiltonians for enhanced quantum control.

Contribution

It introduces a novel approach to spin squeezing in a single, non-interacting ultracold molecule with angular momentum greater than 1/2, using experimentally relevant field configurations.

Findings

Identification of parameter regimes for spin squeezing

Analytical and numerical support for the proposed Hamiltonians

Potential applications in precision spectroscopy and magnetometry

Abstract

In this article we present a concrete proposal for spin squeezing the ultracold ground state polar paramagnetic molecule OH, a system currently under fine control in the laboratory. In contrast to existing work, we consider a single, non-interacting molecule with angular momentum greater than $1/2$. Starting from an experimentally relevant effective Hamiltonian, we identify a parameter regime where different combinations of static electric and magnetic fields can be used to realize the single-axis twisting Hamiltonian of Kitagawa and Ueda [M. Kitagawa and M. Ueda, Phys. Rev. A 47, 5138 (1993)], the uniform field Hamiltonian proposed by Law et al. [C. K. Law, H. T Ng and P. T. Leung, Phys. Rev. A 63, 055601 (2001)], and a model of field propagation in a Kerr medium considered by Agarwal and Puri [G. S. Agarwal and R. R. Puri, Phys. Rev. A 39, 2969 (1989)]. To support our conclusions, we provide analytical expressions as well as numerical calculations, including optimization of field strengths and accounting for the effects of field misalignment. Our results have consequences for applications such as precision spectroscopy, techniques such as magnetometry, and stereochemical effects such as the orientation-to-alignment transition.