Physics Colloquium Fall 2026
Thursdays 4:00 p.m. 104 Physics.
Colloquium organizer: Dr. Xiaojie Wang xiaojiewang@mst.edu
Watch past colloquia on our YouTube Channel
Title: A polarized view of the multi-messenger universe
Abstract: Over the past decade, multi-messenger astronomy has reshaped our view of the high-energy universe. While gravitational waves and cosmic neutrinos have explored many key physical properties of black holes and neutron stars, the plasma dynamics and magnetic field structures in these compact object systems are not yet well studied. Polarimetry provides a direct probe of magnetic field dynamics, geometry of the plasma, radiation mechanisms, and plasma physics across multi-messenger sources. Enabled by the recently launched Imaging X-ray Polarimetry Explorer (IXPE) and upcoming observatories like the Compton Spectrometer and Imager (COSI) in the MeV gamma-ray band, multi-wavelength polarimetry is entering a transformative era. This talk presents the unique scientific breakthroughs achievable through multi-wavelength polarimetry, demonstrating its role as a fundamental pillar of modern multi-messenger astrophysics
Keywords: Polarimetry, plasma dynamics, neutrino, relativistic jet, blazar, gamma-ray burst
Title: Experiments on the Cheap
Abstract:
According to the American Institute of Physics, a little under half of the ~600 new Physics faculty hires in 2023-2024 were into departments with no graduate program. The total number of Physics and Astronomy PhDs awarded in that year was about 2,000 (a 1.5% decrease from the previous year). Graduate students and post-doctoral scholars looking for a faculty position may land in a bachelor's only institution. These departments often operate with very limited funds and securing external grants in this space can be exceptionally difficult. What skills and knowledge are useful when trying to design something that looks like experimental research when your budget may be "thoughts and prayers"? In this talk I'll outline some of the lessons I've learned in my time at a regional, 4-year, public school. These lessons have proven valuable in both the research and teaching labs.
Title
Galaxies, Kilonovae, and Lunar Astronomy: Science with UVEX and Beyond
Keywords
Ultraviolet, UVEX, Sky surveys, Time-domain, Multimessenger, Kilonovae, Autonomous scheduling, Lunar surface, Permanently shadowed regions, Artemis, CLPS
Abstract
The UltraViolet EXplorer (UVEX), launching in 2030, will revolutionize UV astronomy with a synoptic all-sky survey 100 times deeper than GALEX and the first rapidly deployable UV spectroscopic capability for a broad range of science applications. It will discover millions of low-mass, low-metallicity galaxies that serve as local analogs to the first galaxies, measuring their star formation rates. It will obtain UV spectra of the youngest, most metal-poor star-forming regions. In the time domain, UVEX will capture rare phenomena including kilonovae from neutron star mergers and early-phase supernovae, addressing key questions about compact object physics and stellar death. UVEX's early-time observations of neutron star mergers will constrain ejecta composition and emission mechanisms. I will discuss UVEX's science objectives, observing strategy, and the algorithms under development to autonomously plan and execute UVEX's science mission in real time, enabling rapid response to transient events without humans in the loop. Beyond UVEX, I will discuss how the lunar South Pole's permanently shadowed regions offer transformative advantages for next-generation time-domain observatories. These facilities can achieve near-100% duty cycles and wide-field monitoring that is difficult from free-flying spacecraft, directly addressing Astro2020's priority in time-domain and multi-messenger astrophysics while also helping to protect our explorers as we return to the Moon.
Title: Gravitational Waves Astronomy
Speaker: Gabriela González, Louisiana State University
Abstract: Since the first detection by the LIGO-Virgo collaboration of gravitational waves in 2015 from a merger of black holes and in 2017 from the merger of neutrons stars, a new era of gravitational wave astrophysics was started with very bright prospects for the future. The number of observations is now into the hundreds and there are many astrophysical properties of black holes and neutron stars derived from those. I will describe details of the latest discoveries and the exciting prospects for more detections in the future, as well as the technology involved in the current gravitational wave detectors and the challenges and prospects for more sensitive detectors.
Key words: "gravitational waves", "precision instrumentation", "black holes and neutron stars"
Speaker: Dr. Sergey V. Polyakov is the Chief of the Quantum Measurement Division, Physical Measurement Laboratory at National Institute of Standards and Technology(NIST)
Title: The World Where Every Photon Counts
Abstract: Photon counting opens a door into a new world. Quantum effects emerge. Beyond fundamental interest, those effects lead to unprecedented accuracy in measuring light, often surpassing the capabilities of classical sensors. Quantum-enabled photonic techniques can enhance nearly every traditional application in optics: from astronomy to biology and from communications to imaging. I will talk about our recent experiments with faint light that enable practical quantum advantage by demonstrating below-the-shot-noise sensitivity and super-resolution. Let me show you a new world that connects fundamental laws of nature with everyday optical technologies.
A few keywords: Quantum information science and technology, quantum optics, single photon sources and detectors, quantum measurements
Title: Can a Solid Flow? Exploring supersolidity in a 2D Dipolar Quantum Gas
Abstract: A supersolid combines two seemingly incompatible properties: the rigid spatial order of a crystal and the frictionless flow of a superfluid. Proposed more than decades ago and long sought in different system, this state has proven remarkably elusive. The question becomes even subtler in two dimensions, where thermal fluctuations strongly constrain both kinds of order. Ultracold atomic gases offer a clean and tunable setting in which to address it. In this talk, I will describe our experiments on two-dimensional dipolar gases of magnetic erbium atoms, whose long-range, anisotropic dipolar interactions allow superfluidity and density modulation to compete and coexist. Starting from a two-dimensional superfluid, we tilt the atomic dipoles to tune the interactions and drive the gas into a spatially modulated state. I will present evidence for two-dimensional supersolidity with various complementary probes including spontaneous density modulation, interference revealing global phase coherence, and collective excitations that reveal superfluid response. These results open a route to understanding how distinct forms of order coexist in low-dimensional quantum matter.
Keywords: Quantum simulation, supersolids, dipolar quantum system, neutral atoms, Bose-Einstein condensate, two-dimensional system.
Title: How to make the vacuum chiral and cavity induced symmetry breaking in quantum materials
Abstract: Fluctuations of vacuum fields have been the focus of much attention recently due to state-of-the-art cavities that can enhance these fluctuations to a degree where electronic properties of 2D quantum materials can be altered. In this talk, I will first discuss how vacuum fluctuations can be made chiral, that is time-reversal symmetry (TRS) breaking, theoretically and then experimentally [1-2]. Then I will show how TRS breaking results in the cavity induced Chern insulators in graphene-based materials [3-4]. For the rest of the talk, I will focus on our recent results on Quantum Hall Ferromagnetism in a cavity vacuum [5], motivated by the experiments on Quantum Hall effects in split-ring resonators, where we find that enhanced vacuum fluctuations can lead to a quantum phase transition to a novel electronic phase of matter, that we call `compact-core phases’. These states involve ``flanks'' of uniform QHF fluids, separated by a ``compact core'' of doubly occupied orbitals. Remarkably, we found that the photon number probes the order parameter of the transition, providing a possible experimental signature of the electronic transition and the two phases.
Title: Materials theory in the search for quantum spin liquids
Abstract: In the last decade, there has been an enormous push to develop quantum computing infrastructure to tackle major computational challenges in cryptography, quantum simulations, and beyond. So far much attention has been put toward just producing more qubits, the quantum analogue of classical computing bits, and correcting errors thereafter; noise and disruptions require tens-of-thousands of qubits to do useful calculations. Alternatively, turning to new materials and systems that can offer topologically protected states with which to compute could escape this noise problem. One such platform would use non-Abelian anyons to perform braiding operations and compose logic gates, and these anyons are predicted to exist in quantum spin liquids (QSLs).
A QSL is a state of matter in which interacting spins exhibit long-range entanglement yet lack magnetic order even at zero temperature. Verifying whether a candidate material is a QSL consumes a lot of effort in synthesis, characterization, and long time delays in using neutron scattering to probe magnetism. Realistic first-principles calculations are the tool which can help pare down the universe of candidate materials and efficiently allocate experimental effort. In this talk, I will discuss how we can use density functional theory and Wannier function methods to model magnetism in candidate QSLs, specifically, rare-earth delafossites. I will also explain first-principles modeling of the magnetic neutron scattering form factor, a quantity which is critical for interpretation of neutron scattering experiments. Using RuCl3 (one of the most heavily studied candidate QSLs) as an example, theoretical calculations reveal more complicated and interesting features of the magnetization density than one would expect under simplifying assumptions common to the neutron scattering field.
Title: Can Roman’s Strong Lenses Reveal the Small-Scale Structure of Dark Matter?
Abstract: Light from a distant galaxy, bent by a foreground galaxy, forms arcs, where anomalous perturbations to such arcs can reveal dark-matter subhalos too faint to see. However, the individually weak deflections of these dark matter subhalos make them hard to detect and observationally degenerate with structure in the source galaxies and with dark matter halos along the line of sight. In Daylan et al. 2018, we introduced probabilistic cataloging to this gravitational imaging problem, enabling statistical conclusions even when individual subhalos are not detectable. More recently, I led a Roman Wide Field Science program to extend this research from individual HST images to all strong lenses in the anticipated wide-field Roman imaging data, designing optimized surveys (Daylan and Birrer 2023) and forecasting over 100,000 detectable lenses in the planned High-Latitude Wide Area Survey (Wedig et al. 2025). My WFS team is currently organizing a Roman data challenge for strong lenses as we prepare for a major upcoming Cycle 1 effort I co-lead to catalog all strong lenses in the Roman data. Following its August launch, Roman is now in science commissioning, and we look forward to leveraging its strong-lens census to advance our understanding of dark matter microphysics.
Keywords: dark matter, strong lensing, Roman Space Telescope, subhalo mass function
Follow Physics