Novel Extrapolation for Strong Coupling Expansions

TL;DR

This paper introduces a new extrapolation method that improves the accuracy of high order series expansions by re-expressing them in terms of an internal system parameter, demonstrated on a quantum spin ladder.

Contribution

The paper proposes a novel extrapolation scheme for series expansions that significantly enhances their accuracy using an internal parameter, applied to a quantum magnetic system.

Findings

Enhanced accuracy of series expansions using the new extrapolation method.

Successful application to the 1-triplet dispersion in a Heisenberg ladder.

Demonstrated improvement over traditional truncation methods.

Abstract

We present a novel extrapolation scheme for high order series expansions. The idea is to express the series, obtained in orders of an external variable, in terms of an internal parameter of the system. Here we apply this method to the 1-triplet dispersion in an antiferromagnetic $S=1/2$ Heisenberg ladder. By the use of the internal parameter the accuracy of the truncated series is enhanced tremendously.