Mastropietro Vieri
University of Milan, Mathematics Department F. Enriquez, Via Saldini 50, Milan, Italy.
Phys Rev E Stat Nonlin Soft Matter Phys. 2013 Apr;87(4):042121. doi: 10.1103/PhysRevE.87.042121. Epub 2013 Apr 25.
We consider a spin chain given by the XXZ model with a weak next-to-nearest-neighbor perturbation that breaks its exact integrability. We prove that such a system has an ideal metallic behavior (infinite conductivity), by rigorously establishing strict lower bounds on the zero-temperature Drude weight, which are strictly positive. The proof is based on exact renormalization group methods allowing us to prove the convergence of the expansions and to fully take into account the irrelevant terms, which play an essential role in ensuring the correct lattice symmetries. We also prove that the Drude weight verifies the same parameter-free relations as in the absence of the integrability-breaking perturbation.
我们考虑一个由XXZ模型给出的自旋链，其具有一个打破精确可积性的弱次近邻微扰。我们通过严格建立零温德鲁德权重的严格下界（这些下界严格为正），证明了这样一个系统具有理想的金属行为（无限电导率）。该证明基于精确重整化群方法，这使我们能够证明展开式的收敛性，并充分考虑无关项，这些无关项在确保正确的晶格对称性方面起着至关重要的作用。我们还证明，德鲁德权重验证与不存在打破可积性微扰时相同的无参数关系。
