Texas A&M University-Commerce

Department of Physics & Astronomy Colloquium Schedule

Colloquium for Spring 2020

Mar 5

Students research presentation

Feb 27

Computational condensed matter physics

First-principles and multiscale simulations of electrified interfaces: screening of two-dimensional materials for catalytic applications

Dr. Oliviero Andreussi

University of North Texas

Dr. Andreussi earned his undergraduate degree (Italian Laurea, 5-years coursework) in Chemical Physics in 2003 from the University of Pisa and the Scuola Normale Superiore of Pisa. He earned a Ph.D. degree (2008) in Chemical Physics from Scuola Normale Superiore of Pisa. His Ph.D. research topic was on modeling the structure and dynamics of water at interfaces. He had several years of postdoctoral work, at MIT, Oxford, EPFL and the University of Pisa. In 2018, Dr. Andreussi began his appointment as an assistant professor at the Department of Physics of the University of North Texas, where he is currently doing research in computational physics of materials. More information about Dr. Andreussi and his research can be found at

https://sites.google.com/site/olivieroandreussi/home and at www.quantum-environ.org

Abstract

Continuum models of solvation have played a crucial role in the computational characterization of molecules solvated in neutral or electrolyte solutions. Recent advances in the field have extended the capabilities of this class of methods towards the characterization of solvated interfaces, possibly in the presence of an applied electrochemical potential. These recent advances have opened the possibility of modeling heterogeneous catalysis and electrochemistry in a first-principles-based framework, where the multiscale nature of the developed approaches provides a significant reduction of the computational burden while retaining a good accuracy. Here, the core methodological aspects and the most recent features of these recently developed approaches, as implemented in the ENVIRON library (www.quantum-environ.org), will be reviewed. Applications to the study of materials for electrocatalytic reactions will be presented, including a recent systematic screening of two-dimensional materials as electrocatalysts for the hydrogen evolution reaction (HER).

Feb 20

Astronomy

The Once and Future First Galaxies

Dr. Mia Bovill

Texas Christian University

Dr. Mia Sauda Bovill earned BS (2004) degrees in Physics and Astronomy at the University of Maryland before earning a MS (2006) and Ph.D. (2011) in Astronomy at the University of Maryland. Her Astronomy Ph.D. research topic was on simulations of the fossils of the first galaxies in the Local Group. After a year at the University of Texas at Austin, she received a FONDECYT Fellowship at Pontificia Universidad Catolica de Chile where she expanded her study of dwarf galaxies to the Local Volume as part of the Survey of Centaurus A’s Baryonic Structure and the Neighborhood Watch. After her time in Santiago, Dr. Bovill worked at the Space Telescope Science Institute on the detectability of the first stars with the James Webb Space Telescope. In the fall of 2018, Dr. Bovill joined Texas Christian University as an Assistant Professor. At TCU, she is currently continuing her research on the formation, evolution and fate of the first stars and galaxies.

Abstract

The first billion years after the Big Bang consist of the cosmic dark ages, followed by the epoch of the first stars and galaxies. Though the broad strokes of the transition from the cosmic dark ages to the modern universe are known, the details remain elusive. Upcoming observatories such as the James Webb Space Telescope will allow us to observe further into to the era of first light, however direct detection of the first stars and galaxies will be beyond their reach. My work marries cutting edge simulations with current and upcoming observations to constrain the number and properties of the first stars and galaxies both at high redshift and with near field cosmology. I will be presenting new results on the detectability of the first galaxies with the James Webb Space Telescope in addition to the possible detection of the first fossils of the first galaxies beyond our Local Group.

Feb 13

Astrophysics

Neutron Stars as Cosmic Laboratories

Dr. Vanessa Graber

McGill University (Canada)

Dr. Graber earned a master's degree in Physics from Eberhard Karls University Tübingen (Germany) in 2012, and a Ph.D. degree in Applied Mathematics from the University of Southampton (UK) in 2016. Her Ph.D. research focused on the study of neutron stars, in particular, the connection between astrophysics and condensed matter physics. From 2016 to 2019, Dr. Graber worked as a postdoctoral fellow at the McGill Space Institute in Montreal (Canada). In 2020, she began an appointment as a senior postdoctoral researcher at the Institute for Space Sciences in Barcelona (Spain), where she is currently focusing on the population synthesis of isolated neutron stars in the Milky Way. More information about Dr. Graber and her research can be found at https://vanessagraber.github.io/

Abstract

Neutron stars unite many extremes of physics which cannot be reached on Earth, making them excellent cosmic laboratories for the study of dense matter. One exciting example is the presence of superfluid and superconducting components in mature neutron stars. When developing mathematical models to describe these large-scale quantum condensates, physicists tend to focus on the interface between astrophysics and nuclear physics. Connections with low-temperature physics are often ignored. However, there has been dramatic progress in understanding and experimenting with laboratory condensates (from the different phases of superfluid helium to the entire range of superconductors and ultra-cold gases). In this talk, I will provide an overview of what we know about superfluid and superconducting components in neutron stars, and suggest novel ways that we may make progress in understanding neutron star physics using the connections to terrestrial low-temperature condensates.

Jan 30

Special Public Presentation

THE ACCELERATING EXPANDING UNIVERSE

- DARK MATTER, DARK ENERGY, AND EINSTEIN'S COSMOLOGICAL CONSTANT, OR WHY JIM PEEBLES WAS AWARDED HALF OF THE 2019 PHYSICS NOBEL PRIZE

Dr. Bharat Ratra

Kansas State University

Dr. Bharat Ratra earned an MS (1982) degree in physics at the Indian Institute of Technology Delhi, and a Ph.D. degree (1986) in physics at Stanford University. His Ph.D. research was on quantum cosmology and superstrings. He worked as a post-doc at SLAC, Princeton University, Caltech, and MIT. In 1996, Dr. Ratra began his appointment as an assistant professor of physics at Kansas State University, where he is currently a distinguished professor of physics and does research in cosmology. In 1988, Ratra and Jim Peebles proposed the first dynamical dark energy model. More information about Dr. Ratra and his research can be found at

https://www.phys.ksu.edu/people/tt-faculty/ratra-bio.html

Abstract

Dark energy is the leading candidate for the mechanism that is responsible for causing the cosmological expansion to accelerate. In this non-technical talk, Bharat Ratra will describe the astronomical data which persuade cosmologists that (as yet not directly detected) dark energy and dark matter are by far the main components of the energy budget of the universe at the present time. He will review how these observations have led to the development of a quantitative "standard" model of cosmology that describes the evolution of the universe from an early epoch of inflation to the complex hierarchy of structure seen today. He will also discuss the basic physics, and the history of ideas (many developed by Jim Peebles), on which this model is based.

Jan 23

Astronomy

One (disk) ring to rule them all: linking accretion from protostars to supermassive black holes

Dr. Simone Scaringi

Texas Tech University

Dr. Scaringi earned B.Sc (2005) in Mathematics with Astronomy and M.Phil (2007) in Astrophysics from the University of Southampton, and a Ph.D in Astrophysics from the same institution (2010). His Ph.D. research topic was on the applications of machine learning algorithms to large astronomical datasets. Dr. Scaringi worked as a postoc at Radboud University Nijmegen (NL) on the IPHAS Galactic plane survey and data from the Kepler mission. He further obtained a Marie Curie Fellowship which brought him to KU Leuven (BE) in 2012 and a Humboldt Fellowship which brought him to the Max-Planck-Institute for Extraterrestrial Physics in Garching (DE) in 2015. In 2017, Dr. Scaringi began a Faculty appointment at the University of Canterbury (NZ), and in 2018 became Assistant Professor at Texas Tech University where he is currently doing research in astrophysics. More information about Dr. Scaringi can be found at

http://www.phys.ttu.edu/~simo/.

Abstract

From planets to super-massive black holes, accretion (the accumulation of matter on a self-gravitating body through gravity) is the process by which most objects in the Universe grow in mass. Accretion requires angular momentum to be lost from the in-falling material, usually resulting in the formation of a so-called accretion disk. Although the importance of accretion disks have been recognized for many years, the detailed physics and dynamics are still poorly understood. Over the last decade we have been able to link the accretion physics of stellar-mass black holes with those of super-massive black holes, with over nine orders of magnitude difference in mass. However, we do not yet know if the physics of accretion can be extended to include other systems, such as accreting white dwarfs, neutron stars, and young-stellar objects. Although seemingly different observationally, I will show how all these different types of accreting systems have also revealed strikingly similar properties. Being just the "tip of the iceberg", the discoveries I will present suggest that a single unifying physical model might exists to explain how accretion disks behave throughout the Universe, irrespective of the mass, size, or type of the accreting object. I will end the talk by briefly reviewing current and future missions/instruments which will provide exciting new insights into this topic, including the BlackGEM array currently under construction in Chile.