NOTE: registration is required
NOTE: registration is required
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.
This Halloween come join the spookiest party in town at the Physics Halloween Party 2023 on Tuesday, October 31st, from 4pm to 8pm in RCH 112. Dress up in your scariest Halloween costume and spook your fellow physicists. The main event will include a pumpkin carving contest where best prize goes to the team with the best physics-inspired pumpkin. Judges will award the winning team of the pumpkin carving contest with gift cards. Similarly, the person with the best costume will win a gift card. Did I mention, FREE PIZZA! Come enjoy a slice with your fellow physicist.
Note Halloween costumes are optional.
Is what I tell myself. There was a time when I thought I may have discovered it, others did too. Around 2012 several groups including ours found evidence of these quantum excitations in electrical circuits containing nanowires of semiconductor covered by a superconductor. The dramatic signatures were peaks in conductance that appeared under conditions expected from theory for Majorana modes, which are their own anti-modes and may possess non-Abelian properties. But a few years later, similar features in the data were identified due to an interesting, but a more mundane effect - which we call trivial states such as Andreev bound states. Over time more and more data pointed at the trivial and not at the exotic explanation. But because Majorana claims kept coming, this led to some digging and even retractions. What we learned after 10 years is that we have a much better handle on what effects show up in these nanowires, which positions us well for the ultimate Majorana discovery which we should be able to tell apart from all the non-Majorana things we saw. The second lesson we learned is that materials quality of device constituents, superconductors and semiconductors, as well as how samples are fabricated - are the make-or-break factors for making this happen. So while I cannot report an exciting physics discovery, I can walk you through the scientific process that took place, a 10-year event of independent value which taught me how to do science better.
The discovery of moiré materials has enabled condensed matter experimentation in new regimes. In this talk, Kin Fai Mak will discuss the general features of moiré materials built on 2D semiconductors, with a particular focus on the interplay between strong electronic correlations and non-trivial band topology. Specifically, he will discuss how we can explore Hubbard physics and quantum Hall physics under zero magnetic field in these materials. The results may shed light on some of the deepest problems in condensed matter physics.
Dr. Lisa Dang from the Université de Montréal will present a colloquium in the Department of Physics and Astronomy on Tuesday, February 27.