Zvonarev M B, Cheianov V V, Giamarchi T
DPMC-MaNEP, University of Geneva, 24 quai Ernest-Ansermet, 1211 Geneva 4, Switzerland.
Phys Rev Lett. 2009 Sep 11;103(11):110401. doi: 10.1103/PhysRevLett.103.110401. Epub 2009 Sep 8.
We investigate the dynamics of the one-dimensional strongly repulsive spin-1/2 Bose-Hubbard model for filling nu <or= 1. While at nu=1 the system is a Hubbard-Mott insulator exhibiting dynamical properties of the Heisenberg ferromagnet, at nu<1 it is a ferromagnetic liquid with complex spin dynamics. We find that close to the insulator-liquid transition the system admits for a complete separation of spin and density degrees of freedom valid at all energy and momentum scales within the t-J approximation. This allows us to derive the propagator of transverse spin waves and the shape of the magnon peak in the dynamic spin structure factor.
我们研究了填充数ν≤1时一维强排斥自旋-1/2玻色-哈伯德模型的动力学。当ν = 1时，系统是一个具有海森堡铁磁体动力学性质的哈伯德-莫特绝缘体，而当ν<1时，它是一种具有复杂自旋动力学的铁磁液体。我们发现，在绝缘体-液体转变附近，该系统在t-J近似下，在所有能量和动量尺度上，自旋和密度自由度都能完全分离。这使我们能够推导出横向自旋波的传播子以及动态自旋结构因子中磁振子峰的形状。
