Events at Physics |
Events During the Week of October 11th through October 18th, 2026
Monday, October 12th, 2026
- Theory Seminar (High Energy/Cosmology)
- Aspects of Cosmology of Dark Particles & Dark Sectors
- Time: 11:30 am - 1:00 pm
- Place: Chamberlin 5280
- Speaker: Anshuman Maharana, Harish-Chandra Research Institute
- Abstract: Dark particles and sectors are ubiquitous in Beyond the Standard Model (BSM) model building and string compactifications. It is important to develop a systematic understanding of their implications of cosmology. In this talk, we will take steps in this direction by looking at various cosmological implications of moduli, (dark) monopoles and dark relics. We will also discuss a universal aspect of dark sector cosmology -- the cosmic gravitational wave background (the gravitational analogue of the cosmic microwave background.)
- Host: Gary Shiu
- Plasma Physics (Physics/ECE/NE 922) Seminar
- Parity-Time Symmetry of Plasma Waves
- Time: 12:00 pm - 1:00 pm
- Place: 2241 Chamberlin Hall
- Speaker: Hong Qin, University of Wisconsin-Madison
- Abstract: The susceptibility tensor of a homogeneous collisionless magnetized plasma possesses parity-time (PT) symmetry. For a stationary gyrotropic equilibrium, with the wave vector $\mathbf{k}$ and the equilibrium magnetic field $\mathbf{B}_0$ in the x-z plane, the kinetic response satisfies $\chi(\omega^,\mathbf{k})=R\chi(\omega,\mathbf{k})^R$, where $R=\operatorname{diag}(1,-1,1)$. We show that the susceptibility PT-symmetry is a reduced-response-space manifestation of PT symmetry of the underpinning kinetic system. We identify parity P and time reversal T on the complete electromagnetic kinetic eigenmode space and show that the Hamiltonian operator $\mathcal{H}_{\mathrm{VM}}$ of the linearized Vlasov--Maxwell system is PT-symmetric, satisfying $PT\mathcal{H}_{\mathrm{VM}}(PT)^{-1}=\mathcal{H}_{\mathrm{VM}}$. The corresponding PT symmetry of the homogeneous magnetized Vlasov--Poisson eigenproblem is also established. Many kinetic instabilities associated with nonmonotonic distributions, rings, loss cones, and resonant energetic-particle populations are fundamentally spontaneous PT-symmetry breaking, which is achieved through and only through Krein collisions. Three examples demonstrate distinct utilities of this analysis. Definite-sign cyclotron residues protect thermal Bernstein modes from spontaneous PT-symmetry breaking. The nonmonotonic Dory--Guest--Harris distribution permits sign-indefinite residues and Krein collisions, for which we derive an analytical instability threshold and growth rate. The recently discovered mode-pole resonance instability provides a distinct realization of spontaneous PT-symmetry breaking and illustrates how PT symmetry can guide the discovery of kinetic instabilities with applications to fusion energy. These results establish PT symmetry as a structural principle of plasma waves and instabilities and open new directions for studying spectral topology in kinetic plasmas.
- Host: Vladimir Zhdankin
Tuesday, October 13th, 2026
- No events scheduled
Wednesday, October 14th, 2026
- Graduate Program Event
- Prospective Grad Info Session (PhD + MS-Quantum)
- Time: 9:30 am - 10:30 am
- Place: Sign up for this session here:
- Speaker: Sharon Kahn and Alice Kwok, Physics Graduate Coordinators
- Abstract: All Prospective Graduate applicants are welcome to join this Info Session to learn about both PhD and MS-Quantum admissions and program details.
Sign up for this session here: - Host: Sharon Kahn and Alice Kwok
Thursday, October 15th, 2026
- R. G. Herb Condensed Matter Seminar
- An interdisciplinary journey from quantum materials to quantum sensors
- Time: 10:00 am - 11:00 am
- Place: 5310 Chamberlin Hall
- Speaker: Kin Chung Fong, Northeastern University
- Abstract: Quantum science and technology offer unprecedented opportunities to deepen our understanding of nature and enable transformative technologies. Realizing these opportunities, however, requires more than advances within a single discipline. New quantum phenomena must be understood at the level of materials, translated into controllable devices, and ultimately harnessed for increasingly sensitive measurements. This interplay between fundamental physics and device engineering can open pathways that are difficult to envision from any single field of study. In this talk, I will share my journey across quantum materials, quantum devices, and quantum sensing, illustrating how discoveries in one area can create new opportunities in another. We will begin with the unusual properties of Dirac and topological materials and explore how these quantum phenomena manifest in Josephson junctions. We will then turn to how the unique electronic and thermodynamic properties of these materials can be harnessed to develop novel single-photon detectors. Building on these ideas, we will explore two-dimensional van der Waals materials as platforms for miniaturized quantum devices, including qubits and quantum-noise-limited amplifiers. Turning this perspective around, we will then apply quantum sensors to investigate fundamental physics. We will focus on studying the pairing symmetry of unconventional superconductors, including magic-angle twisted graphene and topological Weyl superconductors, and explore how these emerging quantum-sensing technologies could enable new scientific frontiers, from planetary science to the search for axion dark-matter. Together, these examples illustrate how an interdisciplinary approach—connecting materials physics, quantum devices, sensing, and fundamental science—can create new pathways for quantum discovery and technology. References: 1. B. Huang, et. al., “Thermal detection of single photons using Dirac fermions,” Nat. Comm. 17, 3845 (2026). 2. J. Balgley, et. al., "Coherent and compact van der Waals transmon qubits," arXiv:2512.08059 (2025). 3. A. Banerjee, et. al., “Superfluid stiffness of twisted multilayer graphene superconductors,” Nature 638, 93 (2025).
- Host: Tiancheng Song
- Astronomy Colloquium
- Modeling the Chemical and Dynamic Feedback Mechanisms of Planet Formation
- Time: 3:30 pm - 4:30 pm
- Place: 4421 Sterling Hall
- Speaker: Eric van Clepper, WiCOR
- Abstract: Planets form in protoplanetary disks, inheriting the composition of the solids and gas present at their formation location. These PPDs, however, are constantly evolving, with dust growth, fragmentation, and pebble drift driving chemical evolution in the gas. While these effects are beginning to be understood, what is less well constrained is the feedback mechanisms between growing planets and the disks in which they form. In this talk, I will discuss recent work using a variety of computational techniques to create a wholistic, self-consistent model of planet-disk interactions and the resulting disk chemical evolution. By combining constraints from disk observations, meteorite measurements, and exoplanet atmospheres I argue for an active stirring of dust near the orbit of giant planets, vertically mixing small dust grains and driving grain surface chemistry. This stirring may have important implications for the formation and transport of complex organic molecules throughout the disk, including delivery to inner terrestrial planets.
- Host: Coco Zhang
Friday, October 16th, 2026
- Physics Department Colloquium
- Neutron Stars Are Plastic
- Time: 3:30 pm - 4:30 pm
- Place: Chamberlin 2241 -
- Speaker: Matt Caplan, Illinois State University
- Abstract: Neutron star crusts are weird. They are fully ionized plasmas of nuclei at densities reaching 10^14 g/cm^3, but under such high pressure that they freeze into a crystal solid. The elastic properties of this solid are especially important for understanding crust breaking and transients in magnetar outbursts and starquakes, but this material cannot break like terrestrial solids due to the high pressure suppressing the formation of fractures and voids. Fortunately, large scale molecular dynamics simulations make it possible to study breaking, plastic flow, and other behavior beyond linear elasticity. I will present our new molecular dynamics simulations demonstrating that neutron star crusts likely have very simple elastic-perfectly plastic rheology, with many strong analogs to terrestrial materials. If perfect crusts experience brittle failure and flow plastically before reannealing, it's possible that neutron star crusts experience 'cycling' with implications for magnetar outbursts.
- Host: Vladimir Zhdankin