Magnetic ordering and quantum statistical effects in strongly repulsive Fermi-Fermi and Bose-Fermi mixtures

2008/06/16 by Xin Guan, X. -W. Guan, Murray T. Batchelor +3
Physics and Astronomy · #Cold Atom Physics and Bose-Einstein Condensates #Physics of Superconductivity and Magnetism #Quantum many-body systems #cond-mat.stat-mech

paper · pdf · doi:10.1103/physreva.78.023621

published as Phys. Rev. A 78, 023621 (2008) · 23 pages 5 figures

arxiv created 2008/06/16 · openalex publication_date 2008/08/15 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28

Abstract

We investigate magnetic properties and statistical effects in one-dimensional (1D) strongly repulsive two-component fermions and in a 1D mixture of strongly repulsive polarized fermions and bosons. Universality in the characteristics of phase transitions, magnetization, and susceptibility in the presence of an external magnetic field H are analyzed from the exact thermodynamic Bethe ansatz solution. We show explicitly that polarized fermions with a repulsive interaction have antiferromagnetic behavior at zero temperature. A universality class of linear field-dependent magnetization persists for weak and finite strong interaction. The system is fully polarized when the external field exceeds the critical value H_c^F\ensuremath≈\frac8\ensuremathγE_F, where E_F is the Fermi energy and \ensuremathγ is the dimensionless interaction strength. In contrast, the mixture of polarized fermions and bosons in an external field exhibits square-root field-dependent magnetization in the vicinities of H=0 and the critical value H=H_c^M\ensuremath≈\frac16\ensuremathγE_F. We find that a pure boson phase occurs in the absence of the external field, fully polarized fermions and bosons coexist for 0<H<H_c^M, and a fully polarized fermion phase occurs for H\ensuremath\geqslantH_c^M. This phase diagram for the Bose-Fermi mixture is reminiscent of weakly attractive fermions with population imbalance, where the interacting fermions with opposite spins form singlet pairs.

Citations

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