Accession Number:

ADA265554

Title:

Extracting Infinite System Properties from Finite Size Clusters: 'Phase Randomization/Boundary Condition Averaging'

Descriptive Note:

Corporate Author:

NAVAL COMMAND CONTROL AND OCEAN SURVEILLANCE CENTER RDT AND E DIV SAN DIEGO CA

Report Date:

1993-04-01

Pagination or Media Count:

8.0

Abstract:

When electron-electron correlations are important, it is often necessary fo use exact numerical methods, such as Lanczoes diagonalization, to study the full many-body Hamiltonian. Unfortunately, such exact diagonalization methods are restricted to small system sizes. We show that if the Hubbard U term is replaced by a periodic Hubbard term, the full many body Hamiltonian may be exactly solved, even for very large systems, though for low fillings. However, for half-filled systems and large U this approach is not only no longer exact, it no longer improved extrapolation of larger systems. We discuss how generalized randomized variable averaging RAV or phase randomization schemes can be reliably employed to improve extrapolation of large system sizes in this regime. This general approach can be combined with any many-body method and is thus of broad interest and applicability.

Subject Categories:

  • Physical Chemistry
  • Quantum Theory and Relativity

Distribution Statement:

APPROVED FOR PUBLIC RELEASE