State selective cooling of $\mathrm{SU}(N)$ Fermi-gases

TL;DR

This paper explores a method for species selective cooling of $ ext{SU}(N)$ Fermi gases by entropy redistribution during adiabatic loading into an optical lattice, demonstrating improved cooling efficiency through potential manipulation.

Contribution

It introduces a novel cooling technique using species selective trapping and quantifies its effectiveness for different atomic species and configurations.

Findings

Optimal cooling occurs when all levels experience the same potential outside the dimple.

Cooling efficiency improves with entropy redistribution in the species selective potential.

Quantitative analysis for ${}^{87}{ m Sr}$ and ${}^{173}{ m Yb}$ shows practical feasibility.

Abstract

We investigate a species selective cooling process of a trapped $\mathrm{SU}(N)$ Fermi gas using entropy redistribution during adiabatic loading of an optical lattice. Using high-temperature expansion of the Hubbard model, we show that when a subset $N_A < N$ of the single-atom levels experiences a stronger trapping potential in a certain region of space, the dimple, it leads to improvement in cooling as compared to a $\mathrm{SU}(N_A)$ Fermi gas only. We show that optimal performance is achieved when all atomic levels experience the same potential outside the dimple and we quantify the cooling for various $N_A$ by evaluating the dependence of the final entropy densities and temperatures as functions of the initial entropy. Furthermore, considering ${}^{87}{\rm Sr}$ and ${}^{173}{\rm Yb}$ for specificity, we provide a quantitative discussion of how the state selective trapping can be achieved with readily available experimental techniques.