Pair formation and collapse in imbalanced fermion populations with unequal massesG. G. Batrouni1, M. J. Wolak2, F. Hébert1 and V. G. Rousseau3
1 INLN, Université de Nice-Sophia Antipolis, CNRS; 1361 route des Lucioles, 06560 Valbonne, France
2 Centre for Quantum Technologies, National University of Singapore - 117542 Singapore
3 Lorentz-Instituut, Universiteit Leiden - Postbus 9504, 2300 RA, Leiden, The Netherlands
received 11 March 2009; accepted in final form 1 May 2009; published May 2009
published online 3 June 2009
We present an exact quantum Monte Carlo study of the effect of unequal masses on pair formation in fermionic systems with population imbalance loaded into optical lattices. We have considered three forms of the attractive interaction and find in all cases that the system is unstable and collapses as the mass difference increases and that the ground state becomes an inhomogeneous collapsed state. We also address the question of canonical vs. grand canonical ensemble and its role, if any, in stabilizing certain phases.
71.10.Fd - Lattice fermion models (Hubbard model, etc.).
02.70.-c - Computational techniques; simulations.
71.27.+a - Strongly correlated electron systems; heavy fermions.
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