DQC Seminar Series: Decagonal Quasicrystals with Ultracold Atoms
Quasicrystals are aperiodic with long-range order, exhibiting an absence of translation symmetry and featuring 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 the energy spectrum of a crystal 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 describe the design of an experiment in which a quantum gas is confined within a 10-fold rotation-symmetric quasiperiodic optical lattice, and will mention planned first measurements.
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Bio: Charles Brown is an Assistant Professor of Physics and has expertise in the generation and measurement of quantum matter in liquid and gas form. He leads an experimental group at Yale that focuses on trapping ultracold atoms in optical lattices to explore how geometry and topology affect emergent properties in exotic quantum materials. He was awarded the AFOSR YIP and NSF CAREER awards for his work exploring the physics of quantum quasicrystals.
