Physics & Astronomy Colloquium

Dr. Ming Sun, The University of Alabama in Huntsville

Title: Multi-phase medium in galaxy groups and clusters

Abstract: Galaxy groups and clusters are the least massive systems where the bulk of baryons are accounted for and also the most massive systems that are gravitationally bound. They contain a wealth of galaxies sampling the broad spectra of galaxy properties, including the most massive galaxies (and probably the most massive supermassive black holes) and galaxies with the highest velocities in the universe. Galaxy groups and clusters are then ideal systems to study cosmic structure formation and the related baryon physics in multi-phase media. In this talk, I will summarize our works on two kinds of multi-phase objects with synergy in galaxy groups and clusters, X-ray cool cores around the central galaxies and stripped tails behind satellite galaxies. New results from multi-wavelength data, including those from XRISM, MUSE and a recent ALMA large program, will be presented, with the implications and future prospects discussed.

Date:
-
Location:
CP 153

Physics & Astronomy Condensed Matter Seminar

Title: Kinetic magnetism and unconventional pairing: moiré system and electron-doped cuprates 
 
Abstract: The magnetic and superconducting properties of correlated electron systems are traditionally attributed to exchange-driven interactions stemming from Coulomb repulsion. However, recent advances suggest that kinetic mechanisms—arising purely from the motion of doped carriers in a strongly interacting background—can drive both magnetism and unconventional pairing. We explore this unifying paradigm in two distinct systems: moiré heterostructures and electron-doped cuprates. In the moiré system, spin polarons emerge below half-filling and metallic Nagaoka  ferromagnetism appears above, with a pseudogap metal phase predicted at low doping and intermediate fields—characterized by a single-particle gap and doping-dependent magnetization plateau. 
In electron-doped cuprates, using a combination of analytical techniques and large-scale simulations in the square-lattice Hubbard model, we uncover a robust kinetic pairing mechanism enabled by frustration in charge motion. This mechanism allows d-wave superconductivity to coexist with antiferromagnetic order, as holes effectively acquire opposite "charges" on different sublattices due to spin-singlet correlations. Together, these results highlight a common origin of magnetism and superconductivity rooted in kinetic processes, and provide a broadly applicable framework for strong coupling superconductivity in doped Mott insulator.
Date:
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Location:
CP 179
Event Series:

Physics & Astronomy Condensed Matter Seminar

Title: Enhanced and Extended Strange Metallicity due to Coulomb Repulsion and Disorder

Abstract: I will discuss the problem of strange metals, where the traditional notion of Fermi liquid quasiparticles ceases to apply. I will view the problem through the lens of a model of electrons with Hubbard-U Coulomb repulsion and a disordered Yukawa coupling to a two-dimensional bosonic bath, which can be solved in an extended dynamical mean field theory scheme. The model exhibits a quantum critical point, at which the repulsive component of the electron interactions strongly enhances the effects of the quantum critical bosonic fluctuations on the electrons, leading to a breakdown of Fermi liquid physics and the formation of a strange metal with `Planckian' quasiparticle decay rates at low temperatures, although with no holographic dual. Furthermore, the eventual Mott transition that occurs as the repulsion is increased seemingly bounds the maximum decay rate in the strange metal. I will also discuss some applications and collaborations based on this work to the iron-based superconductors and moire materials. Time permitting, I will conclude with future directions to include nonlocal effects.  

Date:
-
Location:
CP 179
Event Series:

Physics & Astronomy Condensed Matter Seminar

Title: Strongly correlated topological phenomena in graphene multilayers

Abstract: Multilayer rhombohedral graphene has recently been experimentally demonstrated to host a panoply of strongly correlated and topological phenomena. In the presence of alignment to hBN, this platform exhibits Chern insulators and the fractional quantum anomalous Hall effect. On the other hand, signatures of unconventional (chiral) superconductivity arise in pristine multilayers. From a theoretical standpoint, several key issues are under active debate. In particular, what is the nature of the moire effect in this setting? How can we understand the emergence of these exotic topological states? I will discuss our progress towards resolving these questions, and highlight broader implications for other material platforms.

Date:
-
Location:
CP 179
Event Series:

KWeek College Meeting

The K-Week College Meeting is where it all begins. Meet your Arts and Sciences family, grab free swag and snacks, and get ready for an unforgettable start.

📅 Thursday, August 21, 2025
📍 1 PM @ Gatton Student Center, Barker Plaza
✅ Attendance will be taken
Date:
-
Location:
Gatton Student Center
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