Unusual metallic phase in a chain of strongly interacting particles

TL;DR

This paper predicts an unusual metallic phase in a one-dimensional lattice model of strongly interacting particles, supported by flux sensitivity calculations, revealing metallic behavior persists at large interactions along a specific parameter line.

Contribution

The study introduces a simple predictive framework for the insulator-metal phase diagram in a 1D lattice model with strong interactions, highlighting a novel weak metallic phase.

Findings

Metallic properties persist at large interactions along a specific parameter line.

Flux sensitivity decreases polynomially with system size near this line.

The system exhibits a weak metallic phase characterized by non-exponential flux sensitivity decay.

Abstract

We consider a one-dimensional lattice model with the nearest-neighbor interaction $V_1$ and the next-nearest neighbor interaction $V_2$ with filling factor 1/2 at zero temperature. The particles are assumed to be spinless fermions or hard-core bosons. Using very simple assumptions we are able to predict the basic structure of the insulator-metal phase diagram for this model. Computations of the flux sensitivity support the main features of the proposed diagram and show that the system maintains metallic properties at arbitrarily large values of $V_1$ and $V_2$ along the line $V_1-2V_2=\gamma J$, where $J$ is the hopping amplitude, and $\gamma\approx1.2$. We think that close to this line the system is a ``weak'' metal in a sense that the flux sensitivity decreases with the size of the system not exponentially but as $1/L^\alpha$ with $\alpha>1$.