Recent progresses of ultracold two-electron atoms

In this topical review, we discuss the recent advances in ultracold two-electron atoms. Owing to their unique electronic level structure and relevant narrow optical transitions, alkaline-earth-like (AEL) atoms with two valence electrons expand our capabilities in exploring unprecedented physical settings, including an emergent SU(N) symmetry, orbital degrees of freedom with spin-exchange interactions, inter-orbital scattering resonances, and synthetic spin-orbit coupling. Here, we discuss in detail the recent experimental developments and the relevant theoretical works with AEL atoms. Finally, we conclude with a brief discussion of the future prospects for studies with AEL atoms.