Past Events

Abstract: Social bonds live in our biology. To understand the computations that allow our brains to form social bonds, my lab studies monogamous prairie voles. Unlike laboratory mice and rats, these rodents often mate for life, parenting together and defending a shared home. We have found that social information is organized at multiple scales in the brain's reward center—from stable encoding in individual neurons to coordinated ensembles—to enable bond formation.

Many-body localization (MBL) is a many-body quantum phenomenon that fails to thermalize under strong disorder. While experimental work on optical lattice systems suggests the existence of a MBL phase in 2D, there have been challenges regarding its existence in two dimensions. The main challenge of MBL in higher dimensions is an avalanche instability: rare regions of weak disorder can act as a thermal bath, which eventually thermalizes the entire system.

The availability of exascale computing resources has enabled numerical modeling of astrophysical fluid dynamics at unprecedented scale, including studies of MHD turbulence on grids with 10,000^{3} cells, or MHD models of black hole accretion in full GR with radiation transport. Results from a diverse range of applications will be presented, including new insights into the structure of radiation-dominated accretion disks, modeling AGN feedback in elliptical galaxies, and turbulence and cosmic ray transport in the interstellar medium.

Abstract: Proteins operate within an aqueous environment that influences their folding, stability, and activity. Membrane proteins have the added complication of being embedded in lipid bilayers that play an equally critical, yet significantly less understood, role. Much like solvent conditions modulate enzyme kinetics and protein interactions in solution, the lipid composition of the membrane performs regulatory functions for membrane proteins, affecting their organization, conformational dynamics, and catalytic output.

Abstract: Weakened magnetic braking (WMB) was originally proposed in 2016 to explain anomalously rapid rotation in old field stars observed by the Kepler mission. The proximate cause was suggested to be a transition in magnetic morphology from larger to smaller spatial scales. In a series of papers over the past five years, we have collected spectropolarimetric measurements to constrain the large-scale magnetic fields for a sample of stars spanning this transition, including a range of spectral types from late F to early K.

Abstract: The Laser Interferometer Gravitational-wave Observatory (LIGO) detected gravitational waves for the first time in 2015. Since then, hundreds more astrophysical observations have been confirmed. To detect these spacetime ripples requires measurement with sub-attometer precision. I will describe the quantum technologies that make such a measurement possible, enabling present and future discoveries.

Host: Ana Maria Rey

Quantum metrology enables some of the world's most sensitive measurements with potentially far-reaching applications in the life sciences. Although the ultrahigh sensitivity of qubit sensors has sparked the imagination of researchers, implementing them in actual devices that enable monitoring cellular processes or detecting diseases remains largely elusive. Overcoming the limitations that hinder the broader application of quantum technology in the life sciences requires advances in both fundamental science and engineering.

How big would Mercury need to be to retain an atmosphere? How close could Venus orbit the Sun before its atmosphere erodes away? Are habitable Earth-like atmospheres even possible around the smallest stars? In this talk, I describe how exoplanet observations are starting to provide insight on what environments permit terrestrial planet atmospheres to thrive.

Abstract: While the properties of soft materials are ultimately dictated by their electronic structure, exploiting this knowledge for the design of non-crystalline materials has long been a formidable computational challenge. I will define conceptual and practical barriers that limit quantum mechanical design in soft materials and discuss recent work aimed at removing these barriers. First, I will describe the development of electronic structure models that leverage AI to operate at coarse-grained resolutions, enabling electronic design in non-crystalline molecular solids and polymers.

The Large Hadron Collider (LHC) at CERN is the most powerful particle accelerator ever constructed. It enables the study of the fundamental structure of matter by providing proton-proton collisions at the unprecedented energy of 6.8 TeV per beam. It delivers an instantaneous luminosity exceeding 2×1034 cm−2s−1 at its two general-purpose detectors, ATLAS and CMS. During high-intensity operation, the LHC now routinely stores energies of 430 MJ per beam—well beyond its original design specifications.

Host: Dylan Taatjes

Due to their strong, long-range, and tunable dipolar interactions, ultracold polar molecules can realize spin-motion models with rich many-body physics. Using a spin encoded in rotational states of fermionic KRb molecules, we demonstrate tuning of Heisenberg XXZ models with electric fields and Floquet engineering of XYZ models with microwave pulse sequences. By controlling motion with optical lattices, we explore highly tunable generalized t-J models. Observing new dynamics and phases predicted for these models also requires low-entropy initial states.

Solar flares and coronal mass ejections (CMEs) are powered by the sudden release of magnetic energy stored in the Sun’s low corona as a result of magnetic reconnection. Understanding these explosive events requires tracking how magnetic fields evolve—not only during, but also before the eruptions. Yet direct measurements of the 3D coronal magnetic field remain a major challenge. In this talk, I will overview what we currently know about the structure of the pre-eruption magnetic field and the physical mechanisms that trigger eruptions.

We live in a world where everything spins! Join CU Wizards on an exciting adventure to discover what that means, how it feels, and why things get weird when they spin! 

Gwen Eccles, CU Physics Demonstration Coordinator, presents the first show of the CU Wizards season that will include hands-on activities for the audience.

Abstract: Achieving ballistic, coherent charge and energy flow in materials at room temperature is a long-standing goal that could unlock ultrafast, lossless energy and information technologies. The key obstacle to overcome is short-range scattering between electronic particles and lattice vibrations (phonons). I will describe two promising avenues for realizing ballistic transport in two-dimensional (2D) semiconductors by harnessing hybridization between electronic particles and long-wavelength excitations.

Abstract: Magnetic reconnection in asymmetric environments such as the solar corona and Earth’s magnetosphere exhibits distinct particle acceleration behavior compared to symmetric cases, due to differences in plasma density and magnetic field across the current sheet. Using 3D hybrid and particle-in-cell simulations, we explore how this asymmetry influences particle acceleration. We find that increasing asymmetry leads to a systematic reduction in particle acceleration efficiency.

Crystallographic defects are always present in solid state materials. Their impact on the fluctuating spin states of magnetic insulators can be significant but is not well understood.  I will present our recent results showing two interesting effects of lattice defects on spin systems. In the triangular lattice magnet KCSO, magneto-transmission measurements of the 1/3 magnetization plateau and spin supersolid phases found unusual satellite lines. We show that though these lines are sharp, they arise from disorder and enable its detailed characterization, here as dilute vacancies.

Abstract: Quantum processors have the potential to significantly advance our understanding of quantum systems. In particular, the programmability of digital quantum devices can enable access to highly tunable quantum dynamics and observables. The central challenge, however, is suppressing errors, making quantum error correction essential for large-scale algorithms.