Impurity-induced multi-body resonances in a Bose gas

Abstract

We investigate the problem of $N$ identical bosons that are coupled to an impurity particle with infinite mass. For non-interacting bosons, we show that a dynamical impurity-boson interaction, mediated by a closed-channel dimer, can induce an effective boson-boson repulsion which strongly modifies the bound states consisting of the impurity and $N$ bosons. In particular, we demonstrate the existence of two universal 'multi-body' resonances, where all multi-body bound states involving any $N$ emerge and disappear. The first multi-body resonance corresponds to infinite impurity-boson scattering length, $a\to +\infty$, while the second corresponds to the critical scattering length $a^{\ast }>0$ beyond which the trimer ($N=2$ bound state) ceases to exist. Crucially, we show that the existence of $a^{\ast }$ ensures that the ground-state energy in the multi-body bound-state region, $\infty >a>a^{\ast }$, is bounded from below, with a bound that is independent of $N$. Thus, even though the impurity can support multi-body bound states, they become increasingly fragile beyond the dimer state. This has implications for the nature of the Bose polaron currently being studied in cold-atom experiments.

arXiv comment5 pages, 3 figures

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Cited by in corpus (17)

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• Universal aspects of a strongly interacting impurity in a dilute Bose condensate
• Fate of the Bose polaron at finite temperature
• Theory of a resonantly interacting impurity in a Bose-Einstein condensate
• Quantum behavior of a heavy impurity strongly coupled to a Bose gas
• Theory of radio-frequency spectroscopy of impurities in quantum gases
• Rydberg impurity in a Fermi gas: Quantum statistics and rotational blockade
• Quantum dynamics of Bose-polaron in a $d$-dimensional Bose Einstein condensate
• Quench Dynamics of the Ideal Bose Polaron at Zero and Nonzero Temperatures
• Pattern formation in one-dimensional polaron systems and temporal orthogonality catastrophe
• Few-body states of bosons interacting with a heavy quantum impurity
• Electronic properties and polaronic dynamics of semi-Dirac system within ladder approximation
• Disorder in order: Localization without randomness in a cold atom system
• Observation of a Halo Trimer in an Ultracold Bose-Fermi Mixture
• A unified theory of strong coupling Bose polarons: From repulsive polarons to non-Gaussian many-body bound states
• Self-stabilized Bose polarons
• Competition of light- and phonon-dressing in microwave-dressed Bose polarons