Past Events

A new sectional cloud model for the NSF Community Earth System Model

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We have developed a new cloud model, CARMA Cloud, for the NCAR Community Earth System Model that is designed to simplify the cloud model and improve its representation of cloud aerosol interactions. Rapid, unexpected, global warming since 2003 seems to be due to a combination of cloud feedback to global warming and strong response to aerosol changes. While the model is currently aimed at terrestrial cloud physics, the basic code has recently been used for exo-planet studies, and an early version of the model was used for studies of Martian ice clouds.

Engineering novel quantum phases in twisted graphene multilayers

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Abstract: Strongly correlated and topological phases in condensed matter systems are at the cutting edge of fundamental physics studies, as well as being promising candidates for the next generation of technological capabilities like quantum computing. In recent years, a remarkable amount of progress has been made in creating and controlling such phases by introducing a small twist angle or lattice mismatch between two-dimensional (2D) materials.

Effects of the Sun’s trajectory through the galaxy on Earth’s climate over the past 10 million years

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Abstract: With the advent of the Gaia space mission, there has been a revolution in astronomers’ ability to precisely locate the interstellar structures the Sun may have encountered on its voyage around the galaxy. We now have the spatial resolution to trace the Sun’s trajectory back through its interstellar environment up to 60 million years in the past (4000 light-years in distance). This timescale is commensurate with the timescale over which we can reconstruct the paleoclimate of Earth from deep ocean foraminiferas.

Regulation of LRRK2: Identifying vulnerabilities for Parkinson's Disease therapeutics

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Parkinson’s Disease (PD) is the second most prevalent neurodegenerative disease, affecting ~10 million people worldwide. One of the most commonly mutated genes in PD codes for Leucine Rich Repeat Kinase 2 (LRRK2). Autosomal dominant mutations in LRRK2 cause familial PD, while mutations in LRRK2 are risk factors for sporadic PD and increased activity of LRRK2’s kinase has been linked to the sporadic form of the disease as well. This has made LRRK2 the main actionable target for PD therapeutics.

There and Back Again: A Journey to the Sun

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Parker Solar Probe successfully completed its prime mission in 2025, measuring solar wind plasma in-situ as close as 8.8 solar radii (~0.04 AU) from the solar photosphere over a series of close-approach orbits. These close approaches to the Sun enable novel exploration of fundamental stellar processes, such as solar wind acceleration, solar wind heating, interplanetary dust destruction, and radial evolution of solar surface structure. These processes leave distinct signatures in near-Sun particle and field observations that allow us to untangle the physical mechanisms driving them.

New Experimental Platforms for Molecular Polaritonics

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Abstract: Polaritons are hybrid light-matter states with unusual properties that arise from strong interactions between a molecular ensemble and the confined electromagnetic field of an optical cavity. Cavity-coupled molecules appear to demonstrate energetics, reactivity, and photophysics distinct from their free-space counterparts, but the mechanisms and scope of these phenomena remain open questions. I will discuss new experimental platforms that the Weichman Lab is developing to investigate molecular reaction dynamics under strong cavity coupling.

Altermagnetism: an unconventional quantum state of matter

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Abstract: Magnetism is the posterchild of how the interplay between electron-electron interactions and quantum physics promotes novel macroscopic phenomena. Historically, the evolution of our understanding of magnetism has been related to the discovery of new paradigms in condensed-matter physics, as exemplified by the connections between antiferromagnetism and Mott insulators, spin glasses and non-ergodic states, and spin liquids and fractionalized excitations.

Photophoretic Flyers: Novel Propulsion for Near-Space Sensing

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While photophoresis, or “light-driven motion,” has long explained how aerosol layers remain aloft in the middle atmosphere, practical applications have only recently been gaining attention. Advances in nanofabrication now allow us to build lightweight structures that can propel themselves upward using photophoretic forces alone. These “photophoretic flyers” can sustain flight in near-space (30–100 km altitudes), a region that is too high for aircraft and balloons and too low for satellites.

Rapid Scan ESR as a Versatile Tool for High-Frequency Spin Dynamics and Quantum Technologies

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Abstract: The development of pulsed Electron Spin Resonance (ESR) spectroscopy at microwave frequencies above 100 GHz remains a challenging and costly task, primarily due to the limited output power of modern high-frequency solid-state electronics. Nonetheless, a range of critical scientific problems—such as dynamic nuclear polarization (DNP) enhancement of NMR and quantum computing applications involving electron spins—necessitate spin relaxation measurements at THz frequencies.

Deep Learning to Overcome Physical Limits in CryoEM and CryoET

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Abstract: CryoEM and cryoET enable imaging of biological specimens frozen in vitreous ice, revealing 3D molecular or cellular structures at high resolution and in their native state. However, cryoET is limited by the “missing-wedge” problem due to restricted tilt angles, and cryoEM often suffers from preferred orientation, resulting in uneven sampling of angular views and leaving parts of Fourier space poorly covered.

Quantum computational sensing

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Abstract: Modern metrology involves a tight integration of sensors with computation. Suppose that a quantum computer were inserted into this pipeline as the first step in receiving and transforming sensor signals, before classical processing. What could be accomplished?  I illustrate the possibilities with three scenarios for which quantum computation may enhance sensing: demodulation of phase shift keyed signals, trajectory discrimination, and RF signal detection.

2 Fast, 2 Furious? Galaxy and Black Hole Formation in the JWST Era

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The launch and commissioning of the James Webb Space Telescope is ushering in a new era in our understanding of our cosmic origins. Galaxies are a fundamental building block of the universe, yet how they formed has remained enigmatic owing to our inability to observe them at early cosmic times. In just its first three years of operation, JWST has already upended our understanding of galaxy and black hole growth in the early universe.

Zooming In: Single-Particle Insights into Nanomaterials for Energy Conversion and Storage

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Abstract: My talk will highlight new directions in probing semiconductor electrochemistry and reactivity at the single-particle and single-molecule level. I will discuss our recent discovery that the band gap renormalization (BGR) effect in 2D semiconductors strongly dictates their current–voltage behaviorin electrochemical cells, providing a new framework to understand solid-state transistor device performance variability.

High fidelity quantum logic on two trapped-ion qubits without ground-state cooling

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Oxford Ionics develops trapped-ion quantum computers.  We are UK headquartered and opened our US office in Boulder last year.  We will present the work we do in Boulder developing our architecture and our future plans to open a lab and  grow the team here.  We will also discuss our recent acquisition by IonQ and what it means for the companies' joint roadmap.

Historical trends in atmospheric humidity over arid and semi-arid regions

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Abstract: An expected consequence of a warming atmosphere is that atmospheric humidity would rise as a result of the dependency of the atmospheric water vapor holding capacity on temperature (the Clausius-Clapeyron relationship).  But this is only true if there is sufficient availability of water to satisfy the rising atmospheric demand.

Love on the Brain: How We Transform Social Interactions Into Lasting Attachment

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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.

Testing stability of 2D many-body localization under 7Li quantum gas microscope

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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.