Multilevel algorithm for quantum-impurity models.

Published

Journal Article

A continuous-time path integral quantum Monte Carlo method using the directed-loop algorithm is developed to simulate the Anderson single-impurity model in the occupation number basis. Although the method suffers from a sign problem at low temperatures, the new algorithm has many advantages over conventional algorithms. For example, the model can be easily simulated in the Kondo limit without time discretization errors. Furthermore, many observables including the impurity susceptibility and a variety of fermionic observables can be calculated efficiently. Finally the new approach allows us to explore a general technique, called the multilevel algorithm, to solve the sign problem. We find that the multilevel algorithm is able to generate an exponentially large number of configurations with an effort that grows as a polynomial in inverse temperature such that configurations with a positive sign dominate over those with negative signs. Our algorithm can be easily generalized to other multi-impurity problems.

Full Text

Duke Authors

Cited Authors

  • Yoo, J; Chandrasekharan, S; Baranger, HU

Published Date

  • March 31, 2005

Published In

Volume / Issue

  • 71 / 3 Pt 2B

Start / End Page

  • 036708 -

PubMed ID

  • 15903634

Pubmed Central ID

  • 15903634

Electronic International Standard Serial Number (EISSN)

  • 1550-2376

International Standard Serial Number (ISSN)

  • 1539-3755

Digital Object Identifier (DOI)

  • 10.1103/physreve.71.036708

Language

  • eng