Phase separation in the Edwards model

TL;DR

This paper investigates the phase diagram of the Edwards model, revealing how charge transport and phase separation occur in a one-dimensional system of spinless fermions coupled to bosons, with implications for correlated materials.

Contribution

It combines numerical and analytical methods to map the ground-state phases of the Edwards model, identifying conditions for metallic, Tomonaga-Luttinger liquid, and phase-separated states.

Findings

Disappearance of long-range order below a critical boson frequency.

Attractive Tomonaga-Luttinger liquid leads to phase separation.

Strong anomalies in photoemission spectra near phase boundaries.

Abstract

The nature of charge transport within a correlated background medium can be described by spinless fermions coupled to bosons in the model introduced by Edwards. Combining numerical density matrix renormalization group and analytical projector-based renormalization methods we explore the ground-state phase diagram of the Edwards model in one dimension. Below a critical boson frequency any long-range order disappears and the system becomes metallic. If the charge carriers are coupled to slow quantum bosons the Tomonaga-Luttinger liquid is attractive and finally makes room for a phase separated state, just as in the t-J model. The phase boundary separating repulsive from the attractive Tomonaga-Luttinger liquid is determined from long-wavelength charge correlations, whereas fermion segregation is indicated by a vanishing inverse compressibility. On approaching phase separation the photoemission spectra develop strong anomalies.