Neutron Scattering and Magnetism, Laboratory for Solid State Physics, ETH Zürich, CH-8093 Zürich, Switzerland.
Department of Medical Imaging and Information Sciences, Interventional Neuroradiology Unit, University Hospitals of Geneva, CH-1211 Geneva, Switzerland and Laboratory for Hydraulic Machines, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland.
Phys Rev Lett. 2013 Sep 6;111(10):107202. doi: 10.1103/PhysRevLett.111.107202. Epub 2013 Sep 3.
Inelastic neutron scattering is used to measure the spin excitation spectrum of the Heisenberg S=1/2 ladder material (C7H10N)2CuBr4 in its entirety, both in the gapped spin liquid and the magnetic field-induced Tomonaga-Luttinger spin liquid regimes. A fundamental change of the spin dynamics is observed between these two regimes. Density matrix renormalization group calculations quantitatively reproduce and help understand the observed commensurate and incommensurate excitations. The results validate long-standing quantum field-theoretical predictions but also test the limits of that approach.
非弹性中子散射被用来测量海森堡 S=1/2 梯状材料（C7H10N）2CuBr4 的自旋激发谱，包括在有能隙的自旋液体区和磁场诱导的 Tomonaga-Luttinger 自旋液体区。在这两个区之间观察到自旋动力学的基本变化。密度矩阵重整化群计算定量地再现并帮助理解了所观察到的有公度和无公度激发。这些结果验证了长期以来的量子场理论预测，但也检验了该方法的极限。
