Mobile impurity in a Fermi sea from the functional renormalization group analytically continued to real time

Kazuhiko Kamikado, Takuya Kanazawa, Shun Uchino

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6 Citations (Scopus)


Motivated by experiments with cold atoms, we investigate a mobile impurity immersed in a Fermi sea in three dimensions at zero temperature by means of the functional renormalization group. We first perform the derivative expansion of the effective action to calculate the ground-state energy and Tan's contact across the polaron-molecule transition for several mass imbalances. Next we study quasiparticle properties of the impurity by using a real-time method recently developed in nuclear physics, which allows one to go beyond the derivative expansion. We obtain the spectral function of the polaron and the effective mass and quasiparticle weight of attractive and repulsive polarons, and clarify how they are affected by mass imbalances.

Original languageEnglish
Article number013612
JournalPhysical Review A
Issue number1
Publication statusPublished - 2017 Jan 17
Externally publishedYes


ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics

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