Competing orders in one-dimensional half-filled multicomponent fermionic cold atoms: The Haldane-charge conjecture

Article

关键词: QUANTUM SPIN CHAINS;    SINE-GORDON MODEL;    ANTIFERROMAGNETIC HEISENBERG CHAIN;    FIELD-THEORY;    HUBBARD-MODEL;    RENORMALIZATION-GROUPS;    SYMMETRY-BREAKING;    CRITICAL-BEHAVIOR;    ARBITRARY SPIN;    GROUND-STATES;   

DOI  :  10.1103/PhysRevB.84.125123

来源: SCIE

【 摘 要 】

We investigate the nature of the Mott-insulating phases of half-filled 2N-component fermionic cold atoms loaded into a one-dimensional optical lattice. By means of conformal field theory techniques and large-scale DMRG calculations, we show that the phase diagram strongly depends on the parity of N. First, we single out charged, spin-singlet degrees of freedom that carry a pseudospin S = N/2, making it possible to formulate a Haldane conjecture: For attractive interactions, we establish the emergence of Haldane insulating phases when N is even, whereas a metallic behavior is found when N is odd. We point out that the N = 1,2 cases do not have the generic properties of each family. The metallic phase for N odd and larger than 1 has a quasi-long-range singlet pairing ordering with an interesting edge-state structure. Moreover, the properties of the Haldane insulating phases with even N further depend on the parity of N/2. In this respect, within the low-energy approach, we argue that the Haldane phases with N/2 even are not topologically protected but equivalent to a topologically trivial insulating phase and thus confirm the recent conjecture put forward by Pollmann et al. [arXiv:0909.4059 (to be published)].

【 授权许可】

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