One-dimensional Bose Polarons across harmonically confined optical lattices

Felipe Isaule Pontificia Universidad Católica de Chile

The progress in realising ultracold atomic mixtures has greatly revitalised the interest in studying impurities immersed in quantum mediums [1]. Amongst them, Bose polarons, i.e. impurities immersed in bosonic baths, have attracted increased attention since their experimental realisation in 2016 [2, 3]. Following these developments, and motivated by the possibility of trapping ultracold atoms in optical lattices [4], the theoretical study of impurities in lattice configurations has emerged as a new platform for studying polaron physics. In this direction, in the past few years, different studies of lattice Bose polarons have revealed intriguing features across the superfluid-to-Mott insulator transition [5-7].

In this work, we study an impurity interacting with a bosonic bath and immersed in a harmonically confined optical lattice. The harmonic confinement enables us to model a realistic scenario and study polaron physics across superfluid and Mott domains. We consider a one-dimensional configuration and study the system theoretically with DMRG simulations for a large number of particles. We reveal that baths with Mott domains produce an enlargement of the polaron cloud and the onset of a sudden orthogonality catastrophe of the polaron quasiparticle.

[1] C. Baroni, G. Lamporesi, and M. Zaccanti, arxiv:2405.14562 (2024). [2] N.B. Jørgensen, L.Wacker, K.T. Skalmstang, M. M. Parish, J. Levinsen, R. S. Christensen, G. M. Bruun and J. J. Arlt J. J., Phys. Rev. Lett. 117, 055302 (2016). [3] M.-G. Hu., M. J. van de Graaff , D. Kedar, J. P. Corson, E. A. Cornell. and D. S. Ji , Phys. Rev. Lett. 117, 055301 (2016). [4] I. Bloch, Nat. Phys. 1, 23 (2005). [5] V. E. Colussi, F. Caleffi, C. Menotti, and A. Recat, Phys. Rev. Lett 130, 173002 (2023). [6] V. R. Yordanov and F. Isaule, J. Phys. B 56, 045301 (2023). [7] F. Isaule, A. Rojo-Francàs, B. Juliá-Díaz, SciPost Phys. Core 7, 049 (2024).