One hole in the two-leg t-J ladder and adiabatic continuity to the non-interacting limit

TL;DR

This study uses DMRG calculations to show that charge modulation in a two-leg t-J ladder with one doped hole can be explained by non-interacting band structure effects, challenging previous claims of exotic Mott physics.

Contribution

It demonstrates that the charge modulation and quasiparticle dispersion changes can be understood without invoking Mott physics, highlighting the adiabatic connection to a non-interacting limit.

Findings

No charge localization observed.

Charge density modulation linked to quasiparticle dispersion minima.

Results align with a non-interacting band-structure perspective.

Abstract

We have carried out density-matrix-renormalization group (DMRG) calculations for the problem of one doped hole in a two-leg $t-J$ ladder. Recent studies have concluded that exotic "Mott" physics --- arising from the projection onto the space of no double-occupied sites --- is manifest in this model system, leading to charge localization and a new mechanism for charge modulation. In contrast, we show that there is no localization and that the charge density modulation arises when the minimum in the quasiparticle dispersion moves away from $\pi$. Although singular changes in the quasiparticle dispersion do occur as a function of model parameters, all the DMRG results can be qualitatively understood from a non-interacting "band-structure" perspective.