# Competing Orders and Unconventional Criticality in the Su-Schrieffer-Heeger Model

## TL;DR

This paper investigates the phase diagram of the 1D Su-Schrieffer-Heeger model with spinless fermions and quantum phonons, revealing new phases and unconventional critical behavior through quantum Monte Carlo simulations.

## Contribution

It provides a revised phase diagram including an extended charge-density-wave phase and links to deconfined quantum criticality, differing from previous studies.

## Key findings

- Discovery of an extended charge-density-wave phase
- Identification of a retardation-driven phase transition
- Observation of unconventional power-law exponents at criticality

## Abstract

The phase diagram of the one-dimensional Su-Schrieffer-Heeger model of spinless fermions coupled to quantum phonons is determined by quantum Monte Carlo simulations. It differs significantly from previous work. In addition to Luttinger liquid and bond-order-wave (BOW) phases, we find an extended charge-density-wave (CDW) phase. Because of different broken symmetries, BOW and CDW phases are connected by a retardation-driven phase transition. Our results are consistent with the theory of the frustrated $XXZ$ chain, including unconventional power-law exponents at criticality, and an interpretation in terms of deconfined quantum criticality via proliferation of solitons.