Solution to the sign problem in a frustrated quantum impurity model

详细信息    查看全文

• 作者：Connor T. Hann^a ; ^{connor.hann@yale.edu} ; Emilie Huffman^a ; Shailesh Chandrasekharan^a ; ^b
• 关键词：Frustration ; Sign problem ; Quantum Monte Carlo ; Fermion ; Strongly correlated ; Impurity
• 刊名：Annals of Physics
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：376
• 期：Complete
• 页码：63-75
• 全文大小：632 K
• 卷排序：376

文摘

In this work we solve the sign problem of a frustrated quantum impurity model consisting of three quantum spin-half chains interacting through an anti-ferromagnetic Heisenberg interaction at one end. We first map the model into a repulsive Hubbard model of spin-half fermions hopping on three independent one dimensional chains that interact through a triangular hopping at one end. We then convert the fermion model into an inhomogeneous one dimensional model and express the partition function as a weighted sum over fermion worldline configurations. By imposing a pairing of fermion worldlines in half the space we show that all negative weight configurations can be eliminated. This pairing naturally leads to the original frustrated quantum spin model at half filling and thus solves its sign problem.