Spectroscopy of dipolar fermions in 2D pancakes and 3D lattices

TL;DR

This paper calculates the recoil-free spectra of dipolar fermions in 2D and 3D optical lattices, accounting for interactions, losses, and broadening effects, with implications for ultracold molecules and atomic clocks.

Contribution

It provides a comprehensive theoretical framework for interpreting spectroscopic measurements of dipolar fermions in optical lattices, including effects of p-wave interactions and spectral broadening.

Findings

Spectra reveal static correlation functions and density moments.

Inclusion of p-wave interactions and losses improves spectral accuracy.

Spectroscopic methods can probe many-body correlations in lattice systems.

Abstract

Motivated by ongoing measurements at JILA, we calculate the recoil-free spectra of dipolar interacting fermions, for example ultracold heteronuclear molecules, in a one-dimensional lattice of two-dimensional pancakes, spectroscopically probing transitions between different internal (e.g., rotational) states. We additionally incorporate p-wave interactions and losses, which are important for reactive molecules such as KRb. Moreover, we consider other sources of spectral broadening: interaction-induced quasiparticle lifetimes and the different polarizabilities of the different rotational states used for the spectroscopy. Although our main focus is molecules, some of the calculations are also useful for optical lattice atomic clocks. For example, understanding the p-wave shifts between identical fermions and small dipolar interactions coming from the excited clock state are necessary to reach future precision goals. Finally, we consider the spectra in a deep 3D lattice and show how they give a great deal of information about static correlation functions, including \textit{all} the moments of the density correlations between nearby sites. The range of correlations measurable depends on spectroscopic resolution and the dipole moment.