Long-lived fermionic Feshbach molecules with tunable $p$-wave interactions

TL;DR

This paper demonstrates that by increasing the binding energy of ultracold fermionic Feshbach molecules, their lifetime can be extended to over a second, enabling better control of $p$-wave interactions for quantum matter research.

Contribution

It provides the first detailed characterization of $p$-wave collisions in ultracold fermionic molecules, showing how to achieve long lifetimes and thermalization regimes.

Findings

Two-body loss coefficient decreases by three orders of magnitude with increased binding energy.

Molecular lifetime exceeds 1 second, 20 times longer than ground-state molecules.

Identifies a regime where elastic collisions dominate, enabling thermalization.

Abstract

Ultracold fermionic Feshbach molecules are promising candidates for exploring quantum matter with strong $p$-wave interactions, however, their lifetimes were measured to be short. Here, we characterize the $p$-wave collisions of ultracold fermionic $^{23}\mathrm{Na}^{40}\mathrm{K}$ Feshbach molecules for different scattering lengths and temperatures. By increasing the binding energy of the molecules, the two-body loss coefficient reduces by three orders of magnitude leading to a second-long lifetime, 20 times longer than that of ground-state molecules. We exploit the scaling of elastic and inelastic collisions with the scattering length and temperature to identify a regime where the elastic collisions dominate over the inelastic ones allowing the molecular sample to thermalize. Our work provides a benchmark for four-body calculations of molecular collisions and is essential for producing a degenerate Fermi gas of Feshbach molecules.