Variational principle for quantum impurity systems in and out of equilibrium: Application to Kondo problems

doi:10.1103/PhysRevB.98.024103

CORC > 理论物理研究所 > 中国科学院理论物理研究所 > 理论物理所科研产出 > 理论物理所1978-2010年知识产出

	Variational principle for quantum impurity systems in and out of equilibrium: Application to Kondo problems
	Ashida, Y ; Shi, T 3; Banuls, MC ; Cirac, JI ; Demler, E 4
刊名	PHYSICAL REVIEW B
	2018
卷号	98 期号:2 页码:24103
关键词	MATRIX PRODUCT STATES MANY-BODY SYSTEM RENORMALIZATION-GROUP ANDERSON MODEL PHASE-TRANSITIONS LOW-TEMPERATURES COHERENT STATES FERMION SYSTEMS MAGNETIC-FIELD DOTS
ISSN号	2469-9950
DOI	10.1103/PhysRevB.98.024103
英文摘要	We provide a detailed formulation of the recently proposed variational approach [Y. Ashida, T. Shi, M.-C. Banuls, J. I. Cirac, and E. Demler, Phys. Rev. Lett. 121, 026805 (2018)] to study ground-state properties and out-of-equilibrium dynamics for generic quantum spin-impurity systems. Motivated by the original ideas of Tomonaga, Lee, Low, and Pines, we construct a canonical transformation that completely decouples the impurity from the bath degrees of freedom. By combining this transformation with a Gaussian ansatz for the fermionic bath, we obtain a family of variational many-body states that can efficiently encode the strong entanglement between the impurity and fermions of the bath. We give a detailed derivation of equations of motions in the imaginary-and real-time evolutions on the variational manifold. We benchmark our approach by applying it to investigate ground-state and dynamical properties of the anisotropic Kondo model and compare results with those obtained using the matrix-product state (MPS) ansatz. We show that our approach can achieve an accuracy comparable to MPS-based methods with several orders of magnitude fewer variational parameters than the corresponding MPS ansatz. Comparisons to the Yosida ansatz and the exact solution from the Bethe ansatz are also discussed. We use our approach to investigate the two-lead Kondo model and analyze its long-time spatiotemporal behavior and the conductance behavior at finite bias and magnetic fields. The obtained results are consistent with the previous findings in the Anderson model and the exact solutions at the Toulouse point.
学科主题	Materials Science ; Physics
语种	英语
内容类型	期刊论文
源URL	[http://ir.itp.ac.cn/handle/311006/22864]
专题	理论物理研究所_理论物理所1978-2010年知识产出
作者单位	1.Chinese Acad Sci, Inst Theoret Phys, CAS Key Lab Theoret Phys, POB 2735, Beijing 100190, Peoples R China 2.Harvard Univ, Dept Phys, Cambridge, MA 02138 USA 3.Univ Tokyo, Dept Phys, Bunkyo Ku, 7-3-1 Hongo, Tokyo 1130033, Japan 4.Max Planck Inst Quantum Opt, Hans Kopfermann Str 1, D-85748 Garching, Germany
推荐引用方式 GB/T 7714	Ashida, Y,Shi, T,Banuls, MC,et al. Variational principle for quantum impurity systems in and out of equilibrium: Application to Kondo problems[J]. PHYSICAL REVIEW B,2018,98(2):24103.
APA	Ashida, Y,Shi, T,Banuls, MC,Cirac, JI,&Demler, E.(2018).Variational principle for quantum impurity systems in and out of equilibrium: Application to Kondo problems.PHYSICAL REVIEW B,98(2),24103.
MLA	Ashida, Y,et al."Variational principle for quantum impurity systems in and out of equilibrium: Application to Kondo problems".PHYSICAL REVIEW B 98.2(2018):24103.