Events

Dr. Varda F. Hagh, University of Chicago

Traditionally, the properties of bulk materials such as elastic moduli or plasticity have been understood from the characteristic scales and symmetries of underlying ordered structures, e.g., atomic crystals or colloidal lattices. However, disordered materials, such as glasses or granular media, have great untapped potential: they can exist in a multitude of metastable states that are distinguished by their microstructure.

Dr. Joshua S. Dillon; University of California, Berkeley

21 cm cosmology promises to become a revolutionary new 3D probe of our universe. With it, we can uncover the astrophysics of the "Cosmic Dawn"—the era of the first stars and galaxies—and test our standard model of cosmology with exquisite precision. Realizing the potential of 21 cm cosmology requires overcoming considerable challenges; the 21 cm signal from neutral hydrogen is buried under astrophysical foregrounds that are orders of magnitude brighter.

Experience the profound surprise of viewing the brilliant evening "star" Venus through our telescope!

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Discover the true form of this season's bright twilight "star"!

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It's summer! Work on your "star-tan" during the July public tour!

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Cross "visit an observatory" off of your bucket list!

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Physics and Astronomy Colloquium- Polarization Resolved Second Harmonic Generation Microscopy for Biomedically Relevant Applications

Speaker: Dr. Danielle Tokarz

Information regarding the structure and function of living tissues and cells is instrumental to the advancement of biochemistry and biophysics. Nonlinear optical microscopy, in particular, second harmonic generation (SHG), can provide such information. For instance, SHG microscopy can be used to visualize several biological tissues, while polarization-sensitive SHG imaging can be used to extract several parameters related to the ultrastructure of biological tissues. In this talk, I will discuss the use of polarization-resolved SHG microscopy to investigate the ultrastructure of collagen in diseased tissues as well as model systems to understand collagen disorganization in these tissues. I will also discuss the use of polarization-resolved SHG microscopy to investigate other biological tissues including the degradation of otoconia, inner ear calcite crystals which act as linear acceleration sensors.

Daniel Rhodes will begin this talk by highlighting the difficulties and challenges that face the 2D community when it comes to exploring new kinds of 2D materials and some potential solutions to overcoming these challenges, particularly for transition metal dichalcogenides. Subsequently, I will follow up with an example of the new kinds of physics that such control over material quality can allow us to explore: the interaction between ferroelectricity and superconductivity.

In the effort to explore quantum matter using x-rays, spatial coherence in x-ray beams is the new frontier, promising fresh insights across various spatiotemporal scales. Yet, fully capitalizing on beam coherence remains a challenge. This seminar introduces a novel approach: by restricting sampling to simple spatial structures, we can more easily track well-defined Fourier transforms. This technique is especially useful during the onset of first-order phase transitions, when antiferromagnetic domains begin to form.

There are many intriguing physical phenomena that are associated with topological features --- global properties that are not discernible locally. The best-known examples are the quantum Hall effects in electronic systems, where insensitivity to local properties manifests itself as robust conductance. In the talk, we first discuss how similar physics can be explored with photons; specifically, how various topological models can be simulated in various photonics systems, from ring resonators to photonic crystals and fiber loops.