Polarons in alkaline-earth-like atoms with multiple background Fermi surfaces

Abstract

We study the impurity problem in a Fermi gas of ¹⁷³Yb atoms near an orbital Feshbach resonance (OFR), where a single moving particle in the ³P₀ state interacts with two background Fermi seas of particles in different nuclear states of the ground ¹S₀ manifold. By employing wave function ansatz to molecule and polaron states, we investigate various properties of the molecule, the attractive polaron, and the repulsive polaron states. In comparison to the case where only one Fermi sea is populated, we find that the presence of an additional Fermi sea acts as an energy shift between the two channels of the OFR. In addition, quantum fluctuations near the Fermi level can also induce sizable effects to various properties of the attractive and repulsive polarons.

Keywords

Fermi gas / alkaline-earth atoms / orbital Feshbach resonance / polaron

References

[1] R. Zhang, Y. Cheng, H. Zhai, and P. Zhang, Orbital Feshbach resonance in alkali-earth atoms, Phys. Rev. Lett. 115(13), 135301 (2015)

[2] G. Pagano, M. Mancini, G. Cappellini, L. Livi, C. Sias, J. Catani, M. Inguscio, and L. Fallani, Strongly interacting gas of two-electron fermions at an orbital Feshbach resonance, Phys. Rev. Lett. 115(26), 265301 (2015)

[3] M. Höfer, L. Riegger, F. Scazza, C. Hofrichter, D. R. Fernandes, M. M. Parish, J. Levinsen, I. Bloch, and S. Fölling, Observation of an orbital interaction-induced Feshbach resonance in Yb¹⁷³, Phys. Rev. Lett. 115(26), 265302 (2015)

[4] Y. Cheng, R. Zhang, and P. Zhang, Orbital Feshbach resonances with a small energy gap between open and closed channels, Phys. Rev. A 93(4), 042708 (2016)

[5] T.-S. Deng, W. Zhang, and W. Yi, Tuning Feshbach resonances in cold atomic gases with interchannel coupling, Phys. Rev. A 96, 050701(R) (2017)

[6] M. Iskin, Two-band superfluidity and intrinsic Josephson effect in alkaline-earth-metal Fermi gases across an orbital Feshbach resonance, Phys. Rev. A 94, 011604(R) (2016)

[7] M. Iskin, Trapped Yb¹⁷³ Fermi gas across an orbital Feshbach resonance, Phys. Rev. A 95(1), 013618 (2017)

[8] J. Xu, R. Zhang, Y. Cheng, P. Zhang, R. Qi, and H. Zhai, Reaching a Fermi-superfluid state near an orbital Feshbach resonance, Phys. Rev. A 94(3), 033609 (2016)

[9] L. He, J. Wang, S. G. Peng, X. J. Liu, and H. Hu, Strongly correlated Fermi superfluid near an orbital Feshbach resonance: Stability, equation of state, and Leggett mode, Phys. Rev. A 94(4), 043624 (2016)

[10] Y.-C. Zhang, S. Ding, and S. Zhang, Collective modes in a two-band superfluid of ultracold alkaline-earth-metal atoms close to an orbital Feshbach resonance, Phys. Rev. A 95, 041603(R) (2017)

[11] S. Wang, J. S. Pan, X. Cui, W. Zhang, and W. Yi, Topological Fulde-Ferrell states in alkaline-earth-metallike atoms near an orbital Feshbach resonance, Phys. Rev. A 95(4), 043634 (2017)

[12] Y. Cheng, R. Zhang, and P. Zhang, Quantum defect theory for the orbital Feshbach resonance, Phys. Rev. A 95(1), 013624 (2017)

[13] J. G. Chen, T. S. Deng, W. Yi, and W. Zhang, Polarons and molecules in a Fermi gas with orbital Feshbach resonance, Phys. Rev. A 94(5), 053627 (2016)

[14] J. Xu and R. Qi, Polaronic and dressed molecular states in orbital Feshbach resonances, arXiv: 1710.00785 (2017)

[15] T. S. Deng, Z. C. Lu, Y. R. Shi, J. G. Chen, W. Zhang, and W. Yi, Repulsive polarons in alkaline-earth-metallike atoms across an orbital Feshbach resonance, Phys. Rev. A 97(1), 013635 (2018)

[16] F. Chevy, Universal phase diagram of a strongly interacting Fermi gas with unbalanced spin populations, Phys. Rev. A 74(6), 063628 (2006)

[17] R. Combescot, A. Recati, C. Lobo, and F. Chevy, Normal state of highly polarized Fermi gases: Simple manybody approaches, Phys. Rev. Lett. 98(18), 180402 (2007)

[18] M. Punk, P. T. Dumitrescu, and W. Zwerger, Polaronto- molecule transition in a strongly imbalanced Fermi gas, Phys. Rev. A 80(5), 053605 (2009)

[19] S. Zöllner, G. M. Bruun, and C. J. Pethick, Polarons and molecules in a two-dimensional Fermi gas, Phys. Rev. A 83, 021603(R) (2011)

[20] M. Klawunn and A. Recati, Fermi polaron in two dimensions: Importance of the two-body bound state, Phys. Rev. A 84(3), 033607 (2011)

[21] M. M. Parish, Polaron-molecule transitions in a twodimensional Fermi gas, Phys. Rev. A 83, 051603(R) (2011)

[22] R. Schmidt, and T. Enss, Excitation spectra and RF response near the polaron-to-molecule transition from the functional renormalization group, Phys. Rev. A 83(6), 063620 (2011)

[23] X. W. Guan, Polaron, molecule and pairing in onedimensional spin-1/2 Fermi gas with an attractive deltafunction interaction, Front. Phys. 7(1), 8 (2012)

[24] C. Trefzger, and Y. Castin, Impurity in a Fermi sea on a narrow Feshbach resonance: A variational study of the polaronic and dimeronic branches, Phys. Rev. A 85(5), 053612 (2012)

[25] M. Koschorreck, D. Pertot, E. Vogt, B. Fröhlich, M. Feld, and M. Köhl, Attractive and repulsive Fermi polarons in two dimensions, Nature 485(7400), 619 (2012)

[26] P. Massignan, M. Zaccanti, and G. Bruun, Polarons, dressed molecules and itinerant ferromagnetism in ultracold Fermi gases, Rep. Prog. Phys. 77(3), 034401 (2014)

[27] R. Schmidt, M. Knap, D. A. Ivanov, J. S. You, M. Cetina, and E. Demler, Universal many-body response of heavy impurities coupled to a Fermi sea: A review of recent progress, Rep. Prog. Phys. 81(2), 024401 (2018)

[28] P. Massignan and G. M. Bruun, Repulsive polarons and itinerant ferromagnetism in strongly polarized Fermi gases, Eur. Phys. J. D 65(1-2), 83 (2011)

[29] P. Massignan, Z. Yu, and G. M. Bruun, Itinerant ferromagnetism in a polarized two-component Fermi gas, Phys. Rev. Lett. 110(23), 230401 (2013)

[30] C. Kohstall, M. Zaccanti, M. Jag, A. Trenkwalder, P. Massignan, G. M. Bruun, F. Schreck, and R. Grimm, Metastability and coherence of repulsive polarons in a strongly interacting Fermi mixture, Nature 485(7400), 615 (2012)

[31] X. Cui and H. Zhai, Stability of a fully magnetized ferromagnetic state in repulsively interacting ultracold Fermi gases, Phys. Rev. A 81, 041602(R) (2010)

[32] S. Pilati, G. Bertaina, S. Giorgini, and M. Troyer, Itinerant ferromagnetism of a repulsive atomic Fermi gas: A quantum Monte Carlo study, Phys. Rev. Lett. 105(3), 030405 (2010)

[33] M. Cetina, M. Jag, R. S. Lous, I. Fritsche, J. T. M. Waldraven, R. Grimm, J. Levinsen, M. M. Parish, R. Schmidt, M. Knap, and E. Demler, Ultrafast manybody interferometry of impurities coupled to a Fermi sea, Science 354(6308), 96 (2016)

[34] G. Valtolina, F. Scazza, A. Amico, A. Burchianti, A. Recati, T. Enss, M. Inguscio, M. Zaccanti, and G. Roati, Exploring the ferromagnetic behaviour of a repulsive Fermi gas through spin dynamics, Nat. Phys. 13(7), 704 (2017)

[35] S. Mondal, D. Inotani, and Y. Ohashi, Closed-channel contribution in the BCS-BEC crossover regime of an ultracold Fermi gas with an orbital Feshbach resonance, arXiv: 1709.00154v1 (2017)

[36] C. Chin, R. Grimm, P. Julienne, and E. Tiesinga, Feshbach resonances in ultracold gases, Rev. Mod. Phys. 82(2), 1225 (2010)

[37] F. Scazza, G. Valtolina, P. Massignan, A. Recati, A. Amico, A. Burchianti, C. Fort, M. Inguscio, M. Zaccanti, and G. Roati, Repulsive Fermi polarons in a resonant mixture of ultracold Li⁶ atoms, Phys. Rev. Lett. 118(8), 083602 (2017)

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