Quantum impurities constitute a fundamental model in many-body physics. Despite their relative simplicity, they provide essential insights into the behavior of strongly correlated systems. In this talk, I will focus on a *composite* quantum impurity — one that exchanges both linear and angular momentum with a many-body bath.

First, I will introduce a diagrammatic framework for studying the angular momentum properties of quantum many-particle systems. This framework extends the Feynman diagram formalism to incorporate angular momentum, enabling novel analytical techniques [1] and numerical advances through diagrammatic Monte Carlo calculations [2, 3].

Next, I will focus on two specific experimental systems — a single molecule embedded in a superfluid helium nanodroplet [4] and a point-like impurity in an ultracold heteronuclear  41K-87Rb Bose mixture [5, 6]. I will discuss how these two systems can — rather unexpectedly — be described in terms of essentially the same model, demonstrating the far-reaching implications of angular momentum dynamics in different subfields of physics.

[1] GB and M. Lemeshko, Phys. Rev. B 96, 085410 (2017)
[2] GB, T. V. Tscherbul, M. Lemeshko, Phys. Rev. Lett. 121, 165301 (2018)
[3] GB, Q. P. Ho, M. Lemeshko, and T. V. Tscherbul, Phys. Rev. B 108, 045115 (2023)
[4] A.S. Chatterley, …, GB, et al., Phys. Rev. Lett. 125, 013001 (2020)
[5] GB, A. Burchianti, F. Minardi, and T. Macrì, Phys. Rev. A 106, 023301 (2022)
[6] GB, T. Macrì, in preparation

Join Zoom Meeting:

https://us06web.zoom.us/j/5081440931

Meeting ID: 508 144 0931

Seminar hosts: Neven Šantić i Matija Čulo