Subradiance of multilevel fermionic atoms in arrays with filling $n \geq 2$

TL;DR

This paper explores the properties of subradiant states in multilevel fermionic atoms at a single site, revealing how fermionic statistics and dipolar interactions lead to dark states, with potential applications in quantum technologies.

Contribution

It provides a comprehensive analysis of single-site dark states for arbitrary filling n, connecting them to total angular momentum states and proposing methods for their coherent preparation.

Findings

Dark states emerge from fermionic statistics and dipolar interactions.

Single-site dark states can be constructed for any filling n.

Possible schemes for coherent state preparation are discussed.

Abstract

We investigate the subradiance properties of $n\geq 2$ multilevel fermionic atoms loaded into the lowest motional level of a single trap (e.g.~a single optical lattice site or an optical tweezer). As pointed out in our previous work [arXiv:1907.05541], perfectly dark subradiant states emerge from the interplay between fermionic statistics and dipolar interactions. While in [arXiv:1907.05541] we focused on the $n=2$ case, here we provide an in-depth analysis of the single-site dark states for generic filling $n$, and show a tight connection between generic dark states and total angular momentum eigenstates. We show how the latter can also be used to understand the full eigenstate structure of the single-site problem, which we analyze numerically. Apart from this, we discuss two possible schemes to coherently prepare dark states using either a Raman transition or an external magnetic field to lift the Zeeman degeneracy. Although the analysis focuses on the single-site problem, we show that multi-site dark states can be trivially constructed in any geometry out of product states of single-site dark states. Finally, we discuss some possible implementations with alkaline-earth(-like) atoms such as $^{171}$Yb or $^{87}$Sr loaded into optical lattices, where they could be used for potential applications in quantum metrology and quantum information.