Abstract
We investigate the problem of N identical bosons that are coupled to an impurity particle with infinite mass. For noninteracting 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 "multibody" resonances, where all multibody bound states involving any N emerge and disappear. The first multibody resonance corresponds to infinite impurity-boson scattering length, a→+, while the second corresponds to the critical scattering length a∗>0 beyond which the trimer (N=2 bound state) ceases to exist. Crucially, we show that the existence of a∗ ensures that the ground-state energy in the multibody bound-state region, >a>a∗, is bounded from below, with a bound that is independent of N. Thus, even though the impurity can support multibody 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.
| Original language | English |
|---|---|
| Article number | 243401 |
| Number of pages | 6 |
| Journal | Physical Review Letters |
| Volume | 121 |
| Issue number | 24 |
| DOIs | |
| Publication status | Published - 14 Dec 2018 |
Keywords
- Gases
- Superfluid phase
- Fermions
Cite this
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Impurity-Induced Multibody Resonances in a Bose Gas. / Shi, Zhe-Yu; Yoshida, Shuhei M.; Parish, Meera M.; Levinsen, Jesper.
In: Physical Review Letters, Vol. 121, No. 24, 243401, 14.12.2018.Research output: Contribution to journal › Article › Research › peer-review
TY - JOUR
T1 - Impurity-Induced Multibody Resonances in a Bose Gas
AU - Shi, Zhe-Yu
AU - Yoshida, Shuhei M.
AU - Parish, Meera M.
AU - Levinsen, Jesper
PY - 2018/12/14
Y1 - 2018/12/14
N2 - We investigate the problem of N identical bosons that are coupled to an impurity particle with infinite mass. For noninteracting 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 "multibody" resonances, where all multibody bound states involving any N emerge and disappear. The first multibody resonance corresponds to infinite impurity-boson scattering length, a→+, while the second corresponds to the critical scattering length a∗>0 beyond which the trimer (N=2 bound state) ceases to exist. Crucially, we show that the existence of a∗ ensures that the ground-state energy in the multibody bound-state region, >a>a∗, is bounded from below, with a bound that is independent of N. Thus, even though the impurity can support multibody 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.
AB - We investigate the problem of N identical bosons that are coupled to an impurity particle with infinite mass. For noninteracting 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 "multibody" resonances, where all multibody bound states involving any N emerge and disappear. The first multibody resonance corresponds to infinite impurity-boson scattering length, a→+, while the second corresponds to the critical scattering length a∗>0 beyond which the trimer (N=2 bound state) ceases to exist. Crucially, we show that the existence of a∗ ensures that the ground-state energy in the multibody bound-state region, >a>a∗, is bounded from below, with a bound that is independent of N. Thus, even though the impurity can support multibody 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.
KW - Gases
KW - Superfluid phase
KW - Fermions
UR - http://www.scopus.com/inward/record.url?scp=85058672289&partnerID=8YFLogxK
U2 - 10.1103/PhysRevLett.121.243401
DO - 10.1103/PhysRevLett.121.243401
M3 - Article
VL - 121
JO - Physical Review Letters
JF - Physical Review Letters
SN - 0031-9007
IS - 24
M1 - 243401
ER -