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We meet every other Thursday at 4:15PM in room P119.

Previous year's GRADTALKS are available here:
- 2016-2017 School Year

Date Speaker Presentation Abstract
October 5th 2017 Guadalupe Maria Barrios Sazo Simulating white dwarf mergers and black widow pulsars with Castro Castro is an adaptive mesh refinement code that solves the compressible hydrodynamics equations for astrophysical flows. The applications of Castro include Type Ia supernovae and core-collapse studies. In this talk I will describe the code capabilities and its role exploring models of white dwarfs (WD) as progenitors for Type Ia supernovae. I will give special emphasis to the white dwarf merger model. In addition, I will mention some initial exploratory efforts made towards simulating a black widow pulsar (BWP). The BWP consists of a millisecond pulsar in a tight binary system with a low mass star. Observations infer intriguing masses for the neutron star, which could be better characterized with simulations.
October 26th 2017 Anya Gura Artificially Layered Ferroelectric Oxides and Their Uses in the Control of Graphene Through Ferroelectric Switching We use a ferroelectric (FE) material to harness the electric functionalities of graphene (Gr) by engineering Gr-FE Field Effect Transistors. In these devices, the underlying FE superlattice layer is used to control the charge state of the Gr channel. By using artificially layered FE superlattices and optimizing parameters during growth and Gr deposition, we have obtained ideal interfaces that result in hysteretic devices. However, our successful devices using PbTiO3/SrTiO3 as the FE layer display a shift of the gating and C-V curves towards positive gate voltages, making the polarization state unstable. We believe this is caused by ordered structural defects that arise during growth of the superlattice. To overcome this obstacle we have designed a hybrid superlattice system consisting of PbTiO3/SrTiO3/PbTiO3/SrRuO3 alternating layers. In these samples the C-V measurements are centered on 0V, providing retention of the polarization state without any applied compensation bias and enabling non-volatile polarization switching as a result of strain applied by an AFM Tip. We studied local changes in conductivity of the Gr and demonstrate the use this technique to design re-writable circuit elements on the graphene-FE hybrid devices.
November 9th 2017 Jeremy Jae Hyeok Chang Dark Matter Phenomenology Although there are a lot of evidences of dark matter, its properties are still puzzling. Finding out the properties is one of most important topics in particle physics. I’ll talk about an overview of dark matter phenomenology including dark matter evidences, candidates, and searches. I’ll mostly focus on Weakly Interacting Massive Particles (WIMP) and the dark photon models along with constraints and direct detection experiments for the models.
TBD Gabriel Santucci GUTs and Nucleon Decay