Controlling quantum phases with electric fields in one-dimensional Hubbard systems

TL;DR

This paper explores how electric fields can induce and control quantum phase transitions in a one-dimensional Hubbard model, revealing distinct insulating and metallic phases with unique properties.

Contribution

It introduces a detailed analysis of electric field-induced phase transitions in a 1D Hubbard chain, identifying three key phases and their characteristics.

Findings

Identification of Mott insulator, metal, and band-like insulator phases.

Metallic phase shows field-dependent kinetic energy and oscillatory pairing and entanglement.

Metallic phase shrinks with increased spin polarization.

Abstract

Quantum systems under electric fields provide a powerful framework for uncovering and controlling novel quantum phases, especially in low-dimensional systems with strong correlations. In this work, we investigate quantum phase transitions induced by an electric potential difference in a one-dimensional half-filled Hubbard chain. By analyzing (i) tunneling and pairing mechanisms, (ii) charge and spin gaps, and (iii) entanglement between the chain halves, we identify three distinct phases: Mott insulator, metal and band-like insulator. The metallic regime, characterized by the closing of both charge and spin gaps, is accompanied by a field-dependent kinetic energy and a quasi-periodic oscillatory behavior of pairing response and entanglement. Although the metallic phase persists for different magnetizations, its extent in the phase diagram shrinks as spin polarization increases.