Phasonic Spectroscopy of a Quantum Gas in a Quasicrystalline Lattice

Abstract

Phasonic degrees of freedom are unique to quasiperiodic structures, and play a central role in poorly-understood properties of quasicrystals from excitation spectra to wavefunction statistics to electronic transport. However, phasons are challenging to access dynamically in the solid state due to their complex long-range character and the effects of disorder and strain. We report phasonic spectroscopy of a quantum gas in a one-dimensional quasicrystalline optical lattice. We observe that strong phasonic driving produces a nonperturbative high-harmonic plateau strikingly different from the effects of standard dipolar driving. Tuning the potential from crystalline to quasicrystalline, we identify spectroscopic signatures of quasiperiodicity and interactions and map the emergence of a multifractal energy spectrum, opening a path to direct imaging of the Hofstadter butterfly.

4 figures, 8 pages, supplemental materials included

References in corpus (4)

• Observation of Topological Phase Transitions in Photonic Quasicrystals
• Interaction dependent heating and atom loss in a periodically driven optical lattice
• Effect of interactions on the localization of a Bose-Einstein condensate in a quasi-periodic lattice
• Two-dimensional optical quasicrystal potentials for ultracold atom experiments