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

Abstract

We investigate magnetic properties and statistical effects in 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 $H_c^F\approx \frac{8}{\gamma }{E}_F$, where $E_F$ is the Fermi energy and $\gamma$ 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 $H=H_c^M\approx \frac{16}{\gamma }{E}_F$. 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 $H\ge H_c^M$. 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.

23 pages 5 figures

References in corpus (14)

• Bosonizing one-dimensional cold atomic gases
• Mixtures of Bosonic and Fermionic Atoms in Optical Lattices
• Instabilities in binary mixtures of one-dimensional quantum degenerate gases
• An exactly solvable model of the BCS-BEC crossover
• Pairing states of a polarized Fermi gas trapped in a one-dimensional optical lattice
• Few-boson dynamics in double wells: From single-atom to correlated-pair tunneling
• Exact Solution of Strongly Interacting Quasi-One-Dimensional Spinor Bose Gases
• Fulde-Ferrell-Larkin-Ovchinnikov superfluidity in one-dimensional optical lattices
• Density-Matrix Renormalization Group Study of Trapped Imbalanced Fermi Condensates
• Spin waves in a one-dimensional spinor Bose gas
• Ferromagnetic behaviour in the strongly interacting two-component Bose gas
• Exact results for the 1D interacting mixed Bose-Fermi gas
• Correlation functions of one-dimensional Bose-Fermi mixtures
• One-dimensional fermionic gases with attractive p-wave interaction in a hard-wall trap