Exploring light-induced phases of 2D materials in a modulated 1D quasicrystal

TL;DR

This paper demonstrates how polarized light can induce and control quantum phase transitions in 2D materials by mapping the problem onto a 1D quasicrystal, revealing complex localization phenomena and multifractal states.

Contribution

It introduces an experimental approach using driven quasiperiodic optical lattices to observe light-induced quantum phases and multifractal states, bridging 2D and 1D systems.

Findings

Observation of localization-delocalization phase transitions

Stabilization of multifractal wavefunctions with elliptical polarization

Enhanced transport with increased quasiperiodic potential

Abstract

Light-induced quantum phases offer the potential for simple and powerful tuning of material properties. For example, simply illuminating 2D materials in the integer quantum Hall regime with polarized light is predicted to drive quantum phase transitions. Such phenomena are largely beyond the current frontier of solid state experiments due to technical limitations on laser intensity and material purity. However, the Harper-Hofstadter mapping which relates a two-dimensional integer quantum Hall system to a 1D quasicrystal enables the same polarization-dependent light-induced phase transitions to be observed using a quantum gas in a driven quasiperiodic optical lattice. We report results of such an experiment. We observe an interlaced phase diagram of localization-delocalization phase transitions as a function of drive polarization and amplitude. Elliptically polarized driving can stabilize an extended critical phase featuring multifractal wavefunctions; we observe signatures of this phenomenon in anomalous polarization-dependent subdiffusive transport. In this regime, increasing the strength of the quasiperiodic potential can enhance rather than suppress transport. These experiments demonstrate a simple method for synthesizing exotic multifractal states and exploring light-induced quantum phases across different dimensionalities.