Trebst S, Monien H, Hamer CJ, Weihong Z, Singh RR
Physikalisches Institut, Universitat Bonn, Nubetaallee 12, 53115 Bonn, Germany.
Phys Rev Lett. 2000 Nov 13;85(20):4373-6. doi: 10.1103/PhysRevLett.85.4373.
We present a new linked cluster expansion for calculating properties of multiparticle excitation spectra to high orders. We use it to obtain the two-particle spectra for systems of coupled spin-half dimers. We find that even for weakly coupled dimers the spectrum is very rich, consisting of many bound states. The number of bound states depends on both geometry of coupling and frustration. Many of the bound states can only be seen by going to sufficiently high orders in the perturbation theory, showing the extended character of the pair attraction.
我们提出了一种新的关联簇展开方法，用于高阶计算多粒子激发谱的性质。我们用它来获得耦合自旋-1/2二聚体系统的双粒子谱。我们发现，即使对于弱耦合二聚体，谱也非常丰富，包含许多束缚态。束缚态的数量取决于耦合几何结构和阻挫。许多束缚态只有在微扰理论中达到足够高的阶数时才能看到，这表明了对吸引的扩展特性。
