Year: 2021
Type: article
Abstract: We analyze the properties of an impurity in a dilute Bose-Einstein condensate (BEC). The quasiparticle residue of a static impurity in an ideal BEC is known to vanish exponentially with increasing particle number, leading to a bosonic orthogonality catastrophe. Here we introduce a conceptually simple variational ansatz for mobile impurities which accurately describes their macroscopic dressing in the regime close to orthogonality, including back-action onto the BEC as well as boson-boson repulsion beyond the Bogoliubov approximation. This ansatz predicts that the orthogonality catastrophe also occurs in the mobile case, whenever the BEC becomes ideal. Finally, we show that our ansatz agrees well with recent experimental results.
Source: Physical Review A
Institutions: Institute of Photonic Sciences, Barcelona Institute of Science and Technology, Max Planck Institute of Quantum Optics, Munich Center for Quantum Science and Technology, Aarhus University, Southern University of Science and Technology, University of Colorado Boulder, Universitat Politècnica de Catalunya
Language: English
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W3122209013