Abstract
We theoretically investigate a Bose-condensed exciton gas out of equilibrium. Within the framework of the combined BCS-Leggett strong-coupling theory with the non-equilibrium Keldysh formalism, we show how the Bose–Einstein condensation (BEC) of excitons is suppressed to eventually disappear, when the system is in the non-equilibrium steady state. The supply of electrons and holes from the bath is shown to induce quasi-particle excitations, leading to the partial occupation of the upper branch of Bogoliubov single-particle excitation spectrum. We also discuss how this quasi-particle induction is related to the suppression of exciton BEC, as well as the stability of the steady state.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
Notes
We briefly note that, some exciton systems with long carrier lifetime (e.g., excitons in Si) can be regarded as (quasi-)equilibrium system. We also note that cold atom systems always have some decay of atoms from the trap, although they are negligible.
References
J.M. Blatt, K.W. Böer, W. Brandt, Phys. Rev. 126, 1691 (1962)
L.V. Keldysh, A.N. Kozlov, Sov. Phys. JETP 27, 521 (1968)
A.A. High et al., Nature 483, 584 (2012)
J.P. Eisenstein, A.H. MacDonald, Nature 432, 691 (2004)
J. Kasprzak et al., Nature 443, 409 (2006)
S. Utsunomiya et al., Nat. Phys. 4, 700 (2008)
K.G. Lagoudakis et al., Nat. Phys. 4, 706 (2008)
A. Amo et al., Nat. Phys. 5, 805 (2008)
H. Stolz et al., New. J. Phys. 14, 105007 (2012)
K. Yoshioka et al., Phys. Rev. B 88, 041201(R) (2013)
M. Alloing et al., Eur. Phys. Lett. 107, 10012 (2014)
C. Chin, R. Grimm, P. Julienne, E. Tiesinga, Rev. Mod. Phys. 82, 1225 (2010)
C.A. Regal, M. Greiner, D.S. Jin, Phys. Rev. Lett. 92, 040403 (2004)
M.W. Zwierlein et al., Phys. Rev. Lett. 92, 120403 (2004)
D.M. Eagles, Phys. Rev. 186, 456 (1969)
A.J. Leggett, Modern Trends in the Theory of Condensed Matter (Springer, Berlin, 1980)
C. Comte, P. Nozières, J. Phys. (Paris) 43, 1069 (1982)
S.A. Moskalenko, D.W. Snoke, Bose–Einstein Condensation of Excitons and Biexcitons and Coherent Nonlinear Optics with Excitons (Cambridge University Press, Cambridge, 2000)
M. Falkenau et al., Phys. Rev. A 106, 163002 (2011)
J. Mahnke et al., J. Phys. B 48, 165301 (2015)
J. Rammer, Quantum Field Theory of Non-equilibrium States (Cambridge University Press, Cambridge, 2007)
M.H. Szymańska, J. Keeling, P.B. Littlewood, Phys. Rev. Lett. 96, 230602 (2006)
M. Yamaguchi, K. Kamide, T. Ogawa, Y. Yamamoto, New J. Phys. 14, 065001 (2012)
J.R. Schrieffer, Theory of Superconductivity (Benjamin Cummings, New York, 1983)
M. Tinkham, Introduction to Superconductivity (Dover, New York, 1975)
M. Yamaguchi et al., Phys. Rev. Lett. 111, 026404 (2013)
M. Yamaguchi et al., Phys. Rev. B 91, 115129 (2015)
Acknowledgments
We thank M. Yamaguchi, R. Okuyama, D. Inotani, H. Tajima, and A. Edelman for useful discussions. RH was supported by a Grand-in-Aid for JSPS fellows. This work was supported by KiPAS project in Keio University. YO was also supported by Grant-in-Aid for Scientific research from MEXT and JSPS in Japan (25400418, 15H00840). Work at Argonne National Laboratory is supported by the U.S. Department of Energy, Office of Basic Energy Sciences under Contract No. DE-AC02-06CH11357.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Hanai, R., Littlewood, P.B. & Ohashi, Y. Non-equilibrium Properties of a Pumped-Decaying Bose-Condensed Electron–Hole Gas in the BCS–BEC Crossover Region. J Low Temp Phys 183, 127–135 (2016). https://doi.org/10.1007/s10909-016-1552-6
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10909-016-1552-6