Effect of the W-term for a t-U-W Hubbard ladder

TL;DR

This paper investigates how the W-term influences pairing correlations in a 2-leg Hubbard ladder, aiming to identify specific processes that enhance pairing, which is crucial for understanding superconductivity mechanisms.

Contribution

The study analyzes individual processes derived from the W-term to determine their specific roles in promoting pairing in the Hubbard ladder.

Findings

Certain processes within the W-term significantly enhance pairing correlations.

The analysis clarifies which simpler processes contribute to pairing enhancement.

Results provide insights into the mechanisms behind pairing in Hubbard models.

Abstract

Antiferromagnetic and d_{x2-y2}-pairing correlations appear delicately balanced in the 2D Hubbard model. Whether doping can tip the balance to pairing is unclear and models with additional interaction terms have been studied. In one of these, the square of a local hopping kinetic energy H_W was found to favor pairing. However, such a term can be separated into a number of simpler processes and one would like to know which of these terms are responsible for enhancing the pairing. Here we analyze these processes for a 2-leg Hubbard ladder.