Simulations of evaporation to deep Fermi degeneracy in microwave-shielded molecules

TL;DR

This paper uses detailed numerical simulations to demonstrate that evaporative cooling of microwave-shielded polar fermionic molecules can achieve deep Fermi degeneracy, aligning well with experimental data and optimizing evaporation parameters.

Contribution

It provides a comprehensive simulation framework incorporating realistic scattering, trap modeling, and Pauli blocking, showing feasibility of reaching below 10% of the Fermi temperature.

Findings

Simulations match experimental evaporation data for NaK molecules.

Optimized evaporation ramps can reach below 10% of the Fermi temperature.

Deep Fermi degeneracy is achievable despite molecular losses.

Abstract

In the quest toward realizing novel quantum matter in ultracold molecular gases, we perform a numerical study of evaporative cooling in ultracold gases of microwave-shielded polar fermionic molecules. Our Monte Carlo simulations incorporate accurate two-body elastic and inelastic scattering cross sections, realistic modeling of the optical dipole trap, and the influence of Pauli blocking at low temperatures. The simulations are benchmarked against data from evaporation studies performed with ultracold NaK molecules, showing excellent agreement. We further explore the prospects for optimizing the evaporation efficiency by varying the ramp rate and duration of the evaporation trajectory. Our simulation shows that it is possible to reach $< 10\%$ of the Fermi temperature under optimal conditions even in the presence of two-body molecular losses.