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Title: High temperature superconductivity in bilayer nickelates

Abstract: The bilayer nickelates are a recently discovered family of high temperature superconductors.  In the wake of a new discovery, there is always a temptation towards classification; how do these materials relate to other families of superconductors, such as the cuprates, iron-based and heavy fermion systems?  In this talk, I will review the key experimental developments in this area in the context of these other families of high temperature superconductors.  Based on recent theoretical studies in my group, I will argue that high temperature superconductivity in bilayer nickelates occurs as a crossover phenomenon from a high spin magnetic state to a low spin metallic state.  

Join us on Thursday, April 16, for Speaking Science 2026: a full-day opportunity for faculty, staff, and graduate students to strengthen science communication skills and build connections across the University of Minnesota. This year we’ll welcome keynote speaker Caitlin Looby, PhD, Great Lakes reporter for the Milwaukee Journal Sentinel, and round out our day with faculty lightning talks; an array of new skills-based and topical breakout sessions; and an afternoon networking reception.

Biography

Caitlin Looby is the Great Lakes reporter at the Milwaukee Journal Sentinel, where she covers environmental issues, climate change and history within the Great Lakes basin. 

She draws on more than a decade of scientific research, including fieldwork in tropical cloud forests, to make complex science accessible to readers. Before joining the Journal Sentinel in 2022, she taught science communication and trained scientists to engage the public at the University of Minnesota. Her work has appeared in university, local, national and international outlets, as well as on radio and in outdoor publications. In 2023, she delivered a TEDx talk on rebuilding public trust in science.

Caitlin holds a bachelor’s degree in molecular and cellular biology from the University of Connecticut, a master’s degree in biotechnology from Kean University and a doctorate degree in biology from the University of California, Irvine.

Purchase tickets to Speaking Science 2026

Departmental purchases/EFS transfers are available for orders of 5+ guests. Please email [email protected] for more information.

Title: Trapping topological electrons in two-dimensional materials

Abstract: Wave-particle duality is one of the most fundamental features of quantum mechanics. Two solid state systems, this duality clearly manifests itself as different phases of matter: metals, which reflect the wave nature of electrons, while so-called Wigner crystals reflect the particle, and therefore classical, nature of electrons in the presence of strong interactions.

However, these are not all quantum mechanics has to offer in solid state systems. They can also give rise to topological nontrivial effects, which, remarkably, can be diagnosed by measuring their Hall conductance.
In this talk, I will introduce anomalous Hall crystals (AHC), which marry the seemingly classical behavior of Wigner crystals with nontrivial topology. These crystals may arise in highly engineered two-dimensional materials, where quantum effects are enhanced by a strong coupling between momentum and pseudospin that results in large Berry curvature. I will discuss when these crystals are stabilized in various model Hamiltonians, and how their nontrivial topology may or may not affect their dynamical properties such as center of mass motion. Finally, I will talk about the possibility of engineering so-called fractional phases out of AHCs.

Title: Using Radio Detectors to Discover the Highest Energy Astrophysical Neutrinos

Abstract: The detection of high energy astrophysical neutrinos is an important step toward understanding the most energetic cosmic accelerators.  IceCube, an observatory at the South Pole, has observed the first astrophysical neutrinos and identified at least one potential source.  However, the best sensitivity at the highest energies comes from detectors that look for coherent radio Cherenkov emission from neutrino interactions. A new suite of experiments aims to discover neutrinos at the highest energies, covering the full astrophysical energy range out to the highest energies, and opening up new phase space for discovery.   I will discuss the Payload for Ultrahigh Energy Observations (PUEO) is a NASA Astrophysics Pioneers Long Duration Balloon Mission, which recently launched from McMurdo Station in Antarctica on December 20, 2025, as well as the Radio Neutrino Observatory in Greenland (RNO-G), an experiment currently under construction at Summit Station in Greenland.

Apply by March 27th.

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Title: Superconductivity in layered nickelates

Abstract: Unconventional superconductivity in proximity to various strongly correlated electronic phases has been a recurring theme in materials as diverse as heavy fermion compounds, cuprates, pnictides, and twisted bilayer graphene. Here we will introduce a new and growing family of layered nickelate superconductors. The initial discovery of superconductivity in infinite-layer nickelates was motivated by looking for an electronic analog of the cuprates. Notable aspects are a doping-dependent superconducting dome, strong magnetic fluctuations, and a landscape of unusual normal state properties from which superconductivity emerges. The subsequent discovery of superconductivity in bulk La 3 Ni 2 O 7  under high pressure is quite intriguing, in that the d-electron configuration is a priori quite different. Recently, we have used epitaxial strain in (La,Pr) 3 Ni 2 O 7  thin films to stabilize superconductivity at ambient pressure, which is promising to extend their experimental study and development.

Title: Cosmological results from the Dark Energy Spectroscopic Instrument

Abstract: A quarter-century after the discovery of the accelerated expansion of the universe, the constraints on dark energy that powers this acceleration have become very good, but the physical nature of dark energy remains elusive.  I will present and discuss cosmological results from the measurement of baryon acoustic oscillations (BAO) in the three years of observations from the Dark Energy Spectroscopic Instrument. These results, when combined with other data, have indicated a possible new anomaly in the behavior of dark energy, which has caused both excitement and consternation in the field of cosmology.  I will discuss these findings and their implication for our understanding of the physics of the universe.

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Title: Probing biological polymers with single-molecule spectroscopy: From disordered complexes to phase separation

Abstract: The functions of proteins have traditionally been linked to their folded structures, but many proteins perform essential functions without being folded. Quantifying the highly dynamic and conformationally diverse ensembles of these intrinsically disordered proteins (IDPs) and their interaction mechanisms is an important aspect of understanding their functions. A remarkable example are highly charged IDPs, which can form high-affinity polyelectrolyte interactions but retain their disorder in the resulting complexes. I will illustrate how combining advanced single-molecule spectroscopy and other biophysical methods with concepts from polymer theory and molecular simulations can reveal the physical mechanisms underlying the dynamics, interactions, and phase separation of disordered proteins.