Strong coupling Bose polarons in a two-dimensional gas

authored by: L. A. Peña Ardila, G. E. Astrakharchik, S. Giorgini
Abstract: We study the properties of Bose polarons in two dimensions using quantum Monte Carlo techniques. Results for the binding energy, the effective mass, and the quasiparticle residue are reported for a typical strength of interactions in the gas and for a wide range of impurity-gas coupling strengths. A lower and an upper branch of the quasiparticle exist. The lower branch corresponds to an attractive polaron and spans from the regime of weak coupling where the impurity acts as a small density perturbation of the surrounding medium to deep bound states which involve many particles from the bath and extend as far as the healing length. The upper branch corresponds to an excited state where due to repulsion a low-density bubble forms around the impurity but might be unstable against decay into many-body bound states. Interaction effects strongly affect the quasiparticle properties of the polaron. In particular, in the strongly correlated regime, the impurity features a vanishing quasiparticle residue, signaling the transition from an almost free quasiparticle to a bound state involving many atoms from the bath.
Organisation(s): QuantumFrontiers
Institute of Theoretical Physics
External Organisation(s): Universitat Politècnica de Catalunya
University of Trento
Type: Article
Journal: Physical Review Research
Volume: 2
Publication date: 26.06.2020
Publication status: Published
Peer reviewed: Yes
ASJC Scopus subject areas: Physics and Astronomy(all)
Electronic version(s): https://doi.org/10.1103/PhysRevResearch.2.023405 (Access: Open)

BibTeX

@article{5fba53aeb3bb401bb911b7e66006aef0,
title = "Strong coupling Bose polarons in a two-dimensional gas",
abstract = "We study the properties of Bose polarons in two dimensions using quantum Monte Carlo techniques. Results for the binding energy, the effective mass, and the quasiparticle residue are reported for a typical strength of interactions in the gas and for a wide range of impurity-gas coupling strengths. A lower and an upper branch of the quasiparticle exist. The lower branch corresponds to an attractive polaron and spans from the regime of weak coupling where the impurity acts as a small density perturbation of the surrounding medium to deep bound states which involve many particles from the bath and extend as far as the healing length. The upper branch corresponds to an excited state where due to repulsion a low-density bubble forms around the impurity but might be unstable against decay into many-body bound states. Interaction effects strongly affect the quasiparticle properties of the polaron. In particular, in the strongly correlated regime, the impurity features a vanishing quasiparticle residue, signaling the transition from an almost free quasiparticle to a bound state involving many atoms from the bath.",
author = "Ardila, {L. A. Pe{\~n}a} and Astrakharchik, {G. E.} and S. Giorgini",
year = "2020",
month = jun,
day = "26",
doi = "10.1103/PhysRevResearch.2.023405",
language = "English",
volume = "2",
journal = "Physical Review Research",
publisher = "American Physical Society",
number = "2",
}