Kiosk 2

CU Chemistry Professor Wei Zhang and his team consisting of chemistry, mechanical engineering and industry (RockyTech) collaborators will present an all new show that highlights the past, present and future of plastics. During this show students will learn more about pros and cons of plastics in our daily life, as well as the innovation that fosters sustainability and recyclability of plastics!

Time-domain astronomy is entering a new era. With JWST, we can now discover and study supernovae in the early universe, while the Rubin Observatory and the Nancy Grace Roman Space Telescope will find rare transients across wide areas and in unprecedented numbers. These complementary facilities are transforming the transient sky into a laboratory for precision astrophysics and cosmology. In this talk, I will show how these observations are opening new ways to study cosmic expansion and probe the physics of the early universe.  High-redshift Type Ia supernovae allow us to test the stability of the standard candles used to trace cosmic acceleration, while strongly lensed supernovae provide an independent route to cosmological distances through time-delay cosmography. I will highlight recent JWST results on both classes of objects and show how they foreshadow the next decade of time-domain astronomy. Together, JWST, Rubin, and Roman will significantly enhance the role of the transient universe as a precision tool for cosmology.

Cloud microphysics—the processes governing droplets, ice, and aerosols at microscopic scales—remains a leading source of uncertainty in weather and climate predictions. These processes shape cloud structure, precipitation, and radiative feedbacks, yet they are neither resolvable in large-scale models nor directly constrained by most observing systems. Bridging the scale gap between observations, microphysical processes, and predictive models is a central challenge in atmospheric science.

This talk presents a data-driven approach to integrating satellite observations, high-fidelity simulations, and subgrid-scale modeling to better constrain and represent cloud microphysics across scales. First, I will present recent work that applies machine learning to infer vertically resolved cloud properties from passive satellite observations, combining multi-modal data sources to reconstruct properties and structure that are not directly observed. This approach provides new observation-informed constraints across regimes and helps bridge the gap between sparse microphysical measurements and global passive observations. Next, I will introduce a complementary framework for learning reduced-order representations of cloud microphysics from high-fidelity particle-based simulations. This surrogate model discovers compact, physically-consistent, and performant representations of cloud droplet dynamics, enabling efficient and interpretable representations of warm cloud processes in weather and climate models. Together, these approaches illustrate a pathway for integrating observations and simulations within a unified data-driven framework. By linking space-based observation to vertically-resolved cloud properties and reduced-order parameterization to droplet-scale details, this work aims to improve the physical realism and predictive capability of atmosphere prediction systems.

As exoplanet science moves towards bigger, noisier datasets, smaller signals, and more complicated physical models, statistical inference is becoming more and more essential. In this talk, I’ll give a tour of my group’s work applying cutting-edge statistical methods in order to: 1) push the limits of exoplanet detection methods-- particularly radial velocity and astrometric methods-- expanding our understanding of what types of planets can exist;  2) look for patterns across populations of planets, informing theories about how planets form and evolve; and 3) maximize the utility of future data, particularly from the Gaia, Roman, and Habitable Worlds Observatories. I will also discuss my work on open-source software, highlighting the widely-used Bayesian orbit-fitting package orbitize! and the summer school Code/Astro.

The first year of a Ph.D. is our last opportunity to gather students heading into every research area and tell them one long-form story. Because they have just finished an undergrad degree, it is also our first opportunity to focus on the interconnections that make us so happy doing physics, to break out of the silos bounding undergrad courses. Also, many aspects of Physics culture can at last be expressed in concrete form, including symmetry/geometry as the drivers of physical insight. I'll offer an approach that focuses on crazy phenomena that make us ask, "How could anything like that possibly happen at all?" After so much education, students are sometimes shocked at how many such questions remain; some are delighted by how many of them are tractable with ideas that are in their heads, but not fully interconnected yet.

This century is witnessing a second quantum revolution, and quantum sensing represents an area in which chemists can make significant contributions. Achieving quantum sensing requires more than precise control of quantum states at the molecular level; it is also crucial to organize molecular qubits so that they function effectively in complex environments. In this seminar, I will discuss materials chemistry approaches to molecular quantum sensors, focusing on their extension from biological systems to engineered materials.
We have recently enabled intracellular quantum sensing by developing molecular quantum nanosensors (MQNs). By encapsulating atomically optimized molecular spin qubits within biocompatible nanocrystals, MQNs achieve highly uniform spin energy levels and enable room-temperature optical detection of molecular spin states inside living cells. Compared with existing quantum sensors, MQNs exhibit superior uniformity, making absolute temperature sensing within cells possible—an achievement that has been challenging to realize with conventional platforms.
I will then show how molecular quantum sensing can be extended into chemically programmable materials. By incorporating photoactive chromophores as components of metal–organic frameworks (MOFs), these MOFs enable spatial organization and chemical accessibility of molecular qubits. This design allows quantum sensors whose spin coherence times respond to surrounding chemical species at room temperature. Finally, I will discuss how controlled molecular assembly leads to multilevel quantum states (qudits). Through precise chromophore arrangement, singlet fission generates spin-correlated quintet triplet pairs with submicrosecond quantum coherence, expanding molecular quantum sensing beyond two-level systems. Together, these examples illustrate how materials chemistry transforms molecular qubits from isolated spin systems into versatile sensing platforms that function across biological and materials environments.

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The Will Lab studies quantum systems of ultracold atoms and molecules. The lab cools atoms and molecules to temperatures less than a millionth of a degree above absolute zero, where atomic behavior is fully governed by quantum mechanics. Under these conditions, the lab controls individual quantum particles and their interactions with high precision using atomic physics tools, enabling novel platforms for many-body quantum physics, quantum simulation, quantum computing, and quantum optics. Their work spans from fundamental physics—including the first molecular Bose–Einstein condensates—to applied quantum technologies such as large-scale atomic tweezer arrays, opening new approaches to quantum information science and quantum networking.

We will have ~125 high school students from 4 different schools presenting projects they have completed this semester under the guidance of PISEC mentors. In addition to the poster session, we will offer lab tours for the students (12:15-1:15pm). This visit to CU and JILA will be an impactful experience for these students as they explore their interests and opportunities in STEM.

Partnerships for Informal Science Education in the Community (PISEC) is the JILA-PFC outreach program that connects university volunteers with local K-12 students to engage in authentic scientific practices. We have programs at the elementary/middle and high school levels, and strive to cultivate students' interest in STEM and support their identities as scientists. Through mutually beneficial partnerships, we work to create pathways into STEM disciplines for youth while also supporting the professional development of university volunteers. 

Condensed matter physics aims to explore and understand various quantum phenomena that emerge from the interactions between nuclei and electrons. Through synthesizing and investigating various crystals, this constructionism approach has led to the discovery of many amazing phenomena, especially when the principles of electron correlation and topology play important roles. The settings of such conventional crystals are often very complicated, making it hard to extract the essential ingredients and understand the underlying physics. In this talk, I will show our efforts on establishing a new paradigm, based on a material known as rhombohedral graphene, which is part of natural graphite. Rhombohedral graphene has the simplest chemistry and structure, yet can be controlled by a set of experimental knobs to exhibit many intriguing phenomena in condensed matter physics. Beyond phenomena that were familiar, I will focus on two newly observed quantum phases of matter, chiral superconductor and fractional quantum anomalous Hall effect. I will show their construction, phenomena, and implications for quantum many-body physics and applications. In the end, I will discuss new opportunities to be explored in this new paradigm.

I will discuss the standards of time and frequency and how these standards have evolved over the centuries. I will present the current definitions of time and frequency and how these definitions are likely to evolve in the coming years.

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