Department of Physics and Astronomy, University of Ghent, Krijgslaan 281, 9000 Gent, Belgium.
Institute for Theoretical Physics III and Center for Integrated Quantum Science and Technology, University of Stuttgart, 70550 Stuttgart, Germany.
Phys Rev Lett. 2018 Aug 31;121(9):090603. doi: 10.1103/PhysRevLett.121.090603.
We study quasiparticle excitations for quantum spin chains with long-range interactions using variational matrix product state techniques. It is confirmed that the local quasiparticle ansatz is able to capture those excitations very accurately, even when the correlation length becomes very large and in the case of topological nontrivial excitation such as spinons. It is demonstrated that the breaking of the Lieb-Robinson bound follows from the appearance of cusps in the dispersion relation, and evidence is given for a crossover between different quasiparticles as the long-range interactions are tuned.
我们使用变分矩阵乘积态技术研究具有长程相互作用的量子自旋链中的准粒子激发。证实了即使在相关长度变得非常大且存在拓扑非平凡激发（如自旋子）的情况下，局域准粒子假设也能够非常准确地捕获那些激发。表明 Lieb-Robinson 边界的破坏源自于色散关系中出现的尖峰，并且在长程相互作用被调谐时，给出了不同准粒子之间的交叉证据。
