Multiparticle spectral properties in the transverse field Ising model by continuous unitary transformations

Benedikt Fauseweh, Götz S. Uhrig
2013 Physical Review B  
The one-dimensional transverse field Ising model is solved by continuous unitary transformations in the high-field limit. A high accuracy is reached due to the closure of the relevant algebra of operators which we call string operators. The closure is related to the possibility to map the model by Jordan-Wigner transformation to non-interacting fermions. But it is proven without referring to this mapping. The effective model derived by the continuous unitary transformations is used to compute
more » ... e contributions of one, two, and three elementary excitations to the diagonal dynamic structure factors. The three-particle contributions have so far not been addressed analytically, except close to the quantum critical point.
doi:10.1103/physrevb.87.184406 fatcat:evi7bzdl3ffrhbb4ecljcracke