# Bose polaron in spherical trap potentials: Spatial structure and quantum depletion

## TL;DR

This paper studies how a localized impurity affects the spatial structure and quantum depletion of a Bose-Einstein condensate in a spherical trap, revealing the roles of impurity interactions and excitation modes.

## Contribution

It provides a detailed analysis of impurity-induced changes in condensate and excitation profiles using Gross-Pitaevskii and Bogoliubov-de Gennes equations, highlighting the effects of impurity interactions.

## Key findings

- Impurity attraction enhances condensate density around it.
- Impurity repulsion suppresses condensate density near it.
- The centrifugal potential and hole excitations significantly influence quantum depletion.

## Abstract

We investigate how the presence of a localized impurity in a Bose-Einstein condensate of trapped cold atoms that interact with each other weakly and repulsively affects the profile of the condensed and excited components at zero temperature. By solving the Gross-Pitaevskii and Bogoliubov-de Gennes equations, we find that an impurity-boson contact attraction (repulsion) causes both components to change in spatial structure in such a way as to be enhanced (suppressed) around the impurity, while slightly declining (growing) in a far region from the impurity. Such behavior of the quantum depletion of the condensate can be understood by decomposing the impurity-induced change in the profile of the excited component with respect to the radial and azimuthal quantum number. A significant role of the centrifugal potential and the "hole" excitation level is thus clarified.