Abstract
We theoretically investigate quantum conductance across a point contact between two strongly-interacting ultracold Fermi gases. We evaluate the tunneling current, taking into account pairing fluctuations in the Fermi gases within the framework of a combined strong-coupling T-matrix approximation with the Schwinger-Keldysh non-equilibrium formalism. We show that quasi-particle conductance is gradually suppressed, as one passes through the BCS–BEC crossover region from the weak-coupling side. On the other hand, with increasing the strength of a pairing interaction, the fluctuation-pair conductance is found to remarkably increase in the crossover region, which is followed by the suppression in the strong-coupling regime.
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References
P. Nozières, S. Schmitt-Rink, J. Low Temp. Phys. 59, 195 (1985)
C.A.R. Sa de Melo, M. Randeria, J.R. Engelbrecht, Phys. Rev. Lett. 71, 3202 (1993)
Y. Ohashi, A. Griffin, Phys. Rev. Lett. 89, 130402 (2002)
C.A. Regal, M. Greiner, D.S. Jin, Phys. Rev. Lett. 92, 040403 (2004)
C. Sanner, E.J. Su, A. Keshet, W. Huang, J. Gillen, R. Gommers, W. Ketterle, Phys. Rev. Lett. 106, 010402 (2011)
M.J.H. Ku, A.T. Sommer, L.W. Cheuk, M.W. Zwierlein, Science 335, 563 (2012)
S. Tsuchiya, R. Watanabe, Y. Ohashi, Phys. Rev. A 80, 033613 (2009)
R. Haussmann, W. Ranter, S. Cerrito, W. Zwerger, Phys. Rev. A 75, 023610 (2009)
T. Kashimura, R. Watanabe, Y. Ohashi, Phys. Rev. A 86, 043622 (2012)
P. van Wyk, H. Tajima, R. Hanai, Y. Ohashi, Phys. Rev. A 93, 013621 (2016)
S. Krinner, D. Stadler, D. Husmann, J.-P. Brantut, T. Esslinger, Nature 517, 64 (2015)
S. Krinner, M. Lebrat, D. Husmann, C. Grenier, J.-P. Brantut, T. Esslinger, Proc. Natl. Acad. Sci. 113, 8144 (2016)
Y. Imry, R. Landauer, Rev. Mod. Phys. 71, S306 (1999)
Y.V. Nazarov, Y.M. Blanter, Quantum Transport: Introduction to Nanoscience (Cambridge University Press, Cambridge, 2009)
S. Datta, Electronic Transport in Mesoscopic Systems (Cambridge University Press, Cambridge, 1995)
C. Chin, R. Grimm, P. Julienne, E. Tiesinga, Rev. Mod. Phys. 82, 1225 (2010)
S. Uchino, M. Ueda, Phys. Rev. Lett. 118, 105303 (2017)
B. Liu, H. Zhai, S. Zhang, Phys. Rev. A 95, 013623 (2017)
J.C. Cuevas, A. Martìn-Rodero, A. Levy Yeyati, Phys. Rev. B 54, 7366 (1996)
J. Rammer, Quantum Field Theory of Non-equilibrium States (Cambridge University Press, Cambridge, 2007)
Acknowledgements
We thank D. Kagamihara and D. Inotani for useful discussions. This work was supported by a Grant-in-aid for Scientific Research from MEXT and JSPS in Japan (Nos. JP18K11345, JP18H05406 and JP19K03689).
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Furutani, K., Ohashi, Y. Strong-Coupling Effects on Quantum Transport in an Ultracold Fermi Gas. J Low Temp Phys 201, 49–57 (2020). https://doi.org/10.1007/s10909-020-02482-7
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DOI: https://doi.org/10.1007/s10909-020-02482-7