TY - JOUR
T1 - Polaron problems in ultracold atoms
T2 - Role of a fermi sea across different spatial dimensions and quantum fluctuations of a bose medium
AU - Tajima, Hiroyuki
AU - Takahashi, Junichi
AU - Mistakidis, Simeon I.
AU - Nakano, Eiji
AU - Iida, Kei
N1 - Funding Information:
Funding: This research was funded by a Grant-in-Aid for JSPS fellows (Grant No. 17J03975) and for Scientific Research from JSPS (Grants No. 17K05445, No. 18K03501, No. 18H05406, No. 18H01211, and No. 19K14619).
Funding Information:
Acknowledgments: The authors thank K. Nishimura, T. Hata, K. Ochi, T. M. Doi, and S. Tsutsui for useful discussion. S.I.M. gratefully acknowledges financial support in the framework of the Lenz-Ising Award of the University of Hamburg.
Publisher Copyright:
© 2021 by the authors. Licensee MDPI, Basel, Switzerland.
PY - 2021/3
Y1 - 2021/3
N2 - The notion of a polaron, originally introduced in the context of electrons in ionic lattices, helps us to understand how a quantum impurity behaves when being immersed in and interacting with a many-body background. We discuss the impact of the impurities on the medium particles by considering feedback effects from polarons that can be realized in ultracold quantum gas experiments. In particular, we exemplify the modifications of the medium in the presence of either Fermi or Bose polarons. Regarding Fermi polarons we present a corresponding many-body diagrammatic approach operating at finite temperatures and discuss how mediated two-and three-body interactions are implemented within this framework. Utilizing this approach, we analyze the behavior of the spectral function of Fermi polarons at finite temperature by varying impurity-medium interactions as well as spatial dimensions from three to one. Interestingly, we reveal that the spectral function of the medium atoms could be a useful quantity for analyzing the transition/crossover from attractive polarons to molecules in three-dimensions. As for the Bose polaron, we showcase the depletion of the background Bose-Einstein condensate in the vicinity of the impurity atom. Such spatial modulations would be important for future investigations regarding the quantification of interpolaron correlations in Bose polaron problems.
AB - The notion of a polaron, originally introduced in the context of electrons in ionic lattices, helps us to understand how a quantum impurity behaves when being immersed in and interacting with a many-body background. We discuss the impact of the impurities on the medium particles by considering feedback effects from polarons that can be realized in ultracold quantum gas experiments. In particular, we exemplify the modifications of the medium in the presence of either Fermi or Bose polarons. Regarding Fermi polarons we present a corresponding many-body diagrammatic approach operating at finite temperatures and discuss how mediated two-and three-body interactions are implemented within this framework. Utilizing this approach, we analyze the behavior of the spectral function of Fermi polarons at finite temperature by varying impurity-medium interactions as well as spatial dimensions from three to one. Interestingly, we reveal that the spectral function of the medium atoms could be a useful quantity for analyzing the transition/crossover from attractive polarons to molecules in three-dimensions. As for the Bose polaron, we showcase the depletion of the background Bose-Einstein condensate in the vicinity of the impurity atom. Such spatial modulations would be important for future investigations regarding the quantification of interpolaron correlations in Bose polaron problems.
KW - Bose–Einstein condensate
KW - Fermi degenerate gases
KW - Impurity
KW - Interpolaron correlations
KW - Polaron
KW - Quantum depletion
KW - Spectroscopy of quasiparticles
KW - Ultracold atoms
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U2 - 10.3390/atoms9010018
DO - 10.3390/atoms9010018
M3 - Article
AN - SCOPUS:85103811840
SN - 2218-2004
VL - 9
JO - Atoms
JF - Atoms
IS - 1
M1 - 18
ER -