Charles Brown [Yale University]

Abstract:

Quasicrystals are aperiodic yet exhibit long-range order, without translation symmetry but with rotational symmetries that are mathematically forbidden in periodic lattices. In 1984, Shechtman performed X-ray diffraction measurements on a metallic alloy, revealing 10-fold rotational symmetry in the diffraction pattern. This work eventually led to the redefinition of what constitutes a crystal, and the recognition of the reality of aperiodic crystals. Shechtman was then awarded the 2011 Nobel prize in chemistry for the discovery of aperiodic crystals.

In recent decades, band structure and its interplay with topology has provided deep insight into intriguing behavior in periodic crystalline quantum materials. However, thirty years after the discovery of aperiodic crystals, the role of the energy spectrum and its interplay with topology is not well-understood for quasicrystals because standard theoretical methods used to study band structure rely on translational symmetry. Quantum simulation of a quasicrystal would open a window into quasicrystalline “band structure” and topology that is difficult to access with theoretical and analytical methods alone.

This talk will detail the design of an experiment in which a quantum gas is confined within a 10-fold rotation-symmetric quasiperiodic optical lattice, which serves as a quasicrystal quantum simulator.

Research Interests: quantum gasses, ultracold atoms, quantum simulation, quasicrystals