Center seminars are organized by the Mathematics Department and the College of Engineering. The Center gratefully acknowledges support from the UMassD Office of the Provost.
Computational Science Seminars (highlighted in gray) are technical talks on a particular research topic.
Lunchtime Computing Talks (highlighted in light blue) will introduce a new computational tool or technique to the broader UMassD community. These informal introductions assume no prior experience and will often feature a hands-on tutorial, so make sure to bring your laptops!
The Physics Colloquium series (highlighted in light red) is organized by the UMassD Department of Physics. If you are interesting in joining through zoom, please email Prof. Robert Fisher (rfisher1 - at - umassd - dot - edu) for the link.
April 22, 2021
NCSU; UMassD; BU
"Physics Colloquia: Student lightning talks"
First Speaker: Noah Wolfe (North Carolina State University), Characterizing Gravitational Wave Signals from Core-Collapse Supernovae Second Speaker: Katie Rink (University of Massachusetts Dartmouth), Environmental Trends and Scattered Light in Advanced LIGO’s 3rd Observing Run Third Speaker: Zachary Weaver (Boston University), Short-Timescale Variability of the Blazer BL Lac using TESS
"Physics Colloquia: How Mars Lost Its Atmosphere (What we know and think in 2021)"
Abstract: The Mars atmosphere is believed to have been stripped away by the sun and the solar wind over time, changing the climate from a warmer and wetter environment early in its history to the cold, dry climate that we observe today. Recent results from NASA’s MAVEN (Mars Atmosphere and Volatile EvolutioN) orbiter offer new insights into physical processes responsible for the atmospheric escape. More recently arrived orbiters, including ESA’s Trace Gas Orbiter and UAE’s Hope mission, should reveal more details about molecular escape and take us a step closer towards understanding the life cycle of water molecules in the Martian atmosphere. In this talk, I will focus on the MAVEN mission. I will introduce its main scientific objectives and present its most important findings up to date in the context of what is presently known about the history of water of Mars. I will describe in more detail the ongoing research of photochemical escape mechanisms that play a key role in complex interactions between the upper layers of planetary atmospheres and stellar radiation and plasma. Understanding energy deposition and transport driven by such processes requires detailed cross sections for the participating atomic and molecular species in reactive and non-reactive regime at high temperatures. These quantities are still not well-known for all atmospheric species – even though they are key inputs to the models used to interpret the observations and can affect long-term predictions about the evolution of the Mars’ atmosphere. Finally, I will offer some science-guided insight into the prospects of terraforming Mars in the not-so-near future.
"Physics Colloquia: Einstein Gravity and Yang-Mills Gravity: Viewed from the Theory of Lie Derivatives"
Abstract: Foundational physics is defined as the invariance of action under local gauge transformations. Different choices of gauge groups lead to different field theories. If on chooses external space-time translation group in flat space-time, one has quantum Yang-Mills (YM) gravity; and if one chooses general coordinate transformations in curved space-time, one has classical Einstein gravity or general relativity. These two formulations of gravity are based on `formally' the same space-time transformations, which turns out to be the vector field in the Lie derivative (1931) (or Pauli's variation, 1921) of arbitrary tensors. We shall briefly discuss these two formulations of gravity based on theory of Lie derivatives.
April 1, 2021
University Of Connecticut
"Physics Colloquia: Quantum Phases of Interacting Spins in One Dimension"
Abstract: The goal of this research is to simulate quantum mechanics, which is known to be a very challenging problem even for the most advanced supercomputers of today. As such, we study the zero-temperature quantum phases of molecular dipoles (spins) in a quasi-one-dimensional zigzag chain. The dipoles can hop around between lattice sites and the interactions between them can be attractive or repulsive. Since the dipole-dipole interaction is long-range, a dipolar many-body system is predicted to feature intriguing phases. We are particularly interested in the quantum phases induced by geometrical frustration, a situation where not all the interactions are satisfied. By using the numerical approximation method known as density matrix renormalization group (DMRG), we study this system and produce a complex phase diagram.
March 22, 2021
Joseph A. Pechkis
California State University Chico
"Physics Colloquia: Compact Sensors with Ultracold Atoms"
Abstract: As the workhorse for modern atomic, molecular, and optical (AMO) physics for the past 30 years, ultracold gases have proven to be extremely robust systems for studying a broad range of physics such as plasmas, cold chemical reactions, and condensed matter systems. In this talk, I will focus on utilizing these systems for compact sensors. I will discuss research guiding atoms in blue-detuned, hollow optical modes of a hollow fiber. Hollow-core optical fibers are particularly attractive platforms as they are capable of supporting light as well as atoms or molecules. The higher order optical modes supported by the fiber allow for large optical depths, low photon scattering rates, and efficient use of guide laser power. I will also discuss experiments demonstrating spatially and temporally resolved magnetometry using Faraday spectroscopy of a confined atomic sample. This work was performed in the Optical Sciences Division at the Naval Research Laboratory in Washington, DC.
March 18, 2021
Institute Queens University
"Physics Colloquia: Direct Detection of Dark Matter Beyond the Weak Scale"
Abstract: There is overwhelming astrophysical and cosmological evidence for the existence of dark matter. For decades, particle physicists thought it must be a very well-motivated class of models falling under the Weakly Interacting Massive Particles (WIMP) paradigm. Though there have been extensive searches for these, a convincing signal remains elusive. We are hence compelled to consider a broader program based on novel theoretical ideas and search strategies. In this colloquium, I will give an overview of my work on new scenarios beyond the WIMP paradigm that can give striking signals of dark matter, accessible in the near future. I will also discuss a model that can explain the recently observed excess of events at the Xenon1T experiment.
"A Fully Conservative Discontinuous Galerkin Method for the Korteweg-de Vries Equation"
Abstract: In this proposal, we present preliminary results for the design, analysis, and implementation of a fully conservative Discontinuous Galerkin (DG) method for the simulation of the solitary wave solutions to the generalized Korteweg-de Vries (KdV) Equation. KdV equations are known to have soliton solutions that do not lose mass and energy over long distances and long periods of time unless acted upon by outside sources. The research on the solution of KdV equations has opened doors to many areas in nonlinear mathematics and theoretical physics and has wide applications in quantum mechanics, plasma physics, fluid mechanics, and so on.
In this work, we build upon the existing literature to create a fully conservative DG Method that allows accurate and long-time evolution of these wave solutions. The key feature of our method is the conservation of the mass, energy and Hamiltonian which is the physical property of the exact solutions for KdV equations. To our knowledge, it is the first DG method that has this property. To achieve the desired conservation properties, our novel idea is to introduce two stabilization parameters in the numerical flux as new unknowns which then allow us to include the two equations enforcing the conservation of energy and Hamiltonian into the formulation of the numerical scheme. As a result, we can rigorously prove the conservation properties of the scheme which are corroborated by numerical tests. This idea can be generalized to design numerical methods for other problems that have conservation properties.
"Physics Colloquia: The Growing Danger of Nuclear Weapons (and how Physicist can help reduce it)"
Abstract: Although today’s nuclear arsenals are not much in the news, they pose enormous risks for all humanity. Moreover, many treaties that have reduced the threat of nuclear weapons are now being abandoned, and enormous resources are scheduled to be spent on new nuclear weapons. We face a renewed nuclear arms race with potentially catastrophic consequences. Historically, physicists have played a critical role in helping the public and decision makers understand the threat posed by nuclear weapons and what can be done to reduce the threat. I will explain the growing nuclear crisis and describe a new project sponsored by the American Physical Society to support and mobilize physicists to reduce the nuclear threat.
"Physics Colloquia: Becoming Interplanetary: A Space Analog for the Moon and Mars"
Abstract: As we head to the Moon and Mars, filmmaker, inventor, and freelance researcher Kai Staats will share the challenges of our species working to become interplanetary. Kai is principal designer and Director of SAM at B2, a hi-fidelity Mars habitat analog at Biosphere 2. Now three weeks into construction, this facility will later in 2021 provide visiting teams an opportunity to live inside a hermetically sealed crew quarters and attached greenhouse with life support enabled by a hybrid mechanical/bioregenerative air recycling system.
SAM was born of the effort to develop SIMOC, a research-grade computer simulation now hosted by National Geographic (ngs.simoc.space), and will in the future become the AI-based control system for SAM.
Kai holds an MSc in Applied Mathematics from the University of Capetown and has worked in the application of evolutionary computation for data analysis in radio and gravitational wave astronomy, and design of antennae for neutrino detectors.
February 11, 2021
"Lunchtime Computing: Basics of AWS Sagemaker"
Abstract: In this presentation, we will cover the basics of using cloud-computing for data science through Amazon Web Services. We will learn how to store datasets in the cloud using S3, analyze data in a remote computing notebook environment using Sagemaker, and deploy machine learning models to the cloud.
February 4, 2021
Iowa State, UMassD, U. Chicago
"Physics Colloquia: Studying the Relationship Between Flare counts and Stellar Properties"
First Speaker: (Iowa State University), Studying the Relationship Between Flare counts and Stellar Properties Second Speaker: Mark Ivan Ugalino (UMassD), Late-Time Dynamical Friction Effects Infinite Disks Third Speaker:George Iskander (University of Chicago), Quantum Entanglement and Thermal Behavior in Charged-Current Weak Interactions
Abstract: This presentation will go over many of the basics of the visualization tool through demonstrations and an interactive style presentation. There will also be a fun challenge to participate in towards the end!
January 28, 2021
"Physics Colloquia: Student talks"
Abstract: In the fall of 2019, students lobbied the Chancellor to cut the campus greenhouse gas emissions to zero by 2030. We established a working group and hired some consultants to assist us in answering this questions. This presentation will cover how that study was conducted, what we learned about our business as usual approach vs a decarbonized approach, and how we would need to phase the transition from using steam to heat and cool the campus to multiple technologies that use electricity.