The Kapitza pendulum, an inverted pendulum that is inherently unstable yet dynamically stabilized by high-frequency modulation of its pivot, is perhaps the most iconic example of dynamical stabilization of a single-particle system. Dynamical stabilization in the quantum many-body regime, however, remains largely unexplored, especially from an experimental perspective. In the first part of this talk, I will discuss experiments on ultracold atoms confined using time-periodic attractive and repulsive Gaussian potentials, the time average of which is zero [1] or positive. The resulting time-independent effective potential closely resembles that of the Kapitza pendulum. These experiments represent a step toward dynamical stabilization in synthetic many-body systems.
The Paul trap, widely used for the confinement of charged particles, probably represents the most notable Kapitza-pendulum-type device. In the second half of this talk, I will discuss precision measurements performed with laser cooled single 173Yb+ ions confined in a Paul trap. In particular, we have measured the hyperfine structures of the 2S1/2 and 2D3/2 states with a relative uncertainty below 10−8. Combined with state-of-the-art atomic structure calculations, these measurements provide updated insights into the deformation and magnetization distribution of the ytterbium nucleus [2], which is itself a quantum many-body system by its very nature.

Neutral-atom arrays have emerged as a leading platform for scalable quantum computing, combining excellent coherence, optical control of large qubit ensembles, and flexible all-to-all connectivity. Achieving fault tolerance, however, requires efficient error detection and correction. Ytterbium offers unique advantages through its metastable-state qubits: leakage to the ground state can be independently detected, converting physical errors into erasures with known locations, while single-photon excitation to Rydberg states enables scalable, high-fidelity two qubit gates. We report progress toward improving two-qubit entangling gate fidelities in a 171Yb array. The gate is primarily limited by the finite Rydberg lifetime; recent upgrades to our ultraviolet excitation system enable higher Rabi frequencies that mitigate this effect. We develop new experimental optimization techniques, and compare our results with simulations to better understand the current limitations. These advances mark a key step toward scalable, fault-tolerant quantum computing with neutral atoms.

Topological pumps provide a powerful method for transporting particles with remarkable precision by slowly and cyclically modulating a lattice potential. This transport is topologically protected - a feature it shares with the quantum Hall effect - making it inherently robust against noise and experimental imperfections.
In this talk, I will introduce a novel paradigm for this concept: moving beyond the transport of individual particles to the pumping of qubits carrying quantum information. Our experiments, which employ ultracold fermions in dynamical optical lattices, demonstrate the coherent transport of not only single atoms but also entangled atom pairs over hundreds of lattice sites. This capability allows us to perform fundamental quantum computations during transport, including high-fidelity two-qubit gates. I will show how we can chain these operations together to build non-local quantum circuits and generate complex entanglement patterns across the lattice.

Many anticipated discoveries in fundamental science demand better measurement sensitivity. For acoustic sensors, mechanical dissipation sets this limit via the fluctuation-dissipation theorem. Yet, even in high-purity crystals, its microscopic origin remains poorly understood, and external enhancement, such as tension-induced dissipation dilution, is difficult to realize. Here, we realize a strain-engineered diamond nanomechanical platform using van der Waals self-assembly that harnesses surface forces to apply tensile stress exceeding 1 GPa. At cryogenic temperatures, these resonators achieve quality factors beyond 10^10. This exceptional coherence allows us to resolve residual dissipation channels, elucidating distinct two-level systems and topological dissipation from a surface superfluid helium film. Advancing mechanical coherence therefore opens access to new regimes of physics in hybrid quantum systems, precision metrology, and condensed-matter physics.

Continuous-variable quantum systems enable encoding complex states in fewer modes through large-scale non-Gaussian states. Motion, as a continuous degree of freedom, underlies phenomena from Cooper pair dynamics to levitated macroscopic objects. Hence, realizing high-energy, spatially extended motional states remains key for advancing quantum sensing, simulation, and foundational tests.
In the talk, I will present the following control tasks for various nonlinear mechanical systems, including trapped atoms, levitated particles, and clamped oscillators with spin-motion coupling.
(i) Nonharmonic potential modulation: Optimal control of a particle in a nonharmonic potential enables the generation of non-Gaussian states and arbitrary unitaries within a chosen two-level subspace.
(ii) Macroscopic quantum states of levitated particles: Rapid preparation of a particle’s center of mass in a macroscopic superposition is achieved by releasing it from a harmonic trap into a static double-well potential after ground-state cooling.
(iii) Phase-insensitive displacement sensing: For randomized phase-space displacements, quantum optimal control identifies number-squeezed cat states as optimal for force sensitivity under lossy dynamics.
These approaches exploit either intrinsic nonharmonicity or coherent nonlinear coupling, providing a unified framework for motion control in continuous-variable quantum systems—from levitated nanoparticles to optical and microwave resonators—paving the way toward universal quantum control of mechanical degrees of freedom.

The dynamics of Earth’s radiation belts remain one of the central challenges in space weather research. Despite decades of satellite observations, predicting when and how the belts will intensify or decay remains difficult. This seminar will discuss recent work combining multi-mission datasets from 36 multi-agency satellites to produce the highest-resolution phase space density (PSD) observations of the outer belt to date, and how these have been used to identify dominant acceleration and loss mechanisms. New developments in data-assimilative modelling through the Radiation Belt Forecasting Model and Framework (RBFMF) will also be discussed, including how diminishing real-time data coverage affects operational hindcasts. The results highlight the need for continuous, strategically placed measurements through the heart of the radiation belts and improved understanding of which orbital configurations most effectively enhance prediction capability.

Active systems are driven out of equilibrium by exchanging energy and momentum with their environment. This endows them with anomalous mechanical properties which leads to rich phenomena when active fluids are in contact with boundaries, inclusions, or disordered potentials. Indeed, studies of the mechanical pressure of active fluids and of the dynamics of passive tracers have shown that active systems impact their environment in non-trivial ways, for example, by propelling and rotating anisotropic inclusions. Conversely, the long-ranged density and current modulations induced by localized obstacles show how the environment can have a far-reaching impact on active fluids. This is best exemplified by the propensity of bulk and boundary disorder to destroy bulk phase separation in active matter, showing active systems to be much more sensitive to their surroundings than passive ones.

Since 2019, the CUbit Quantum Seminar Series at the University of Colorado Boulder has been a cornerstone of Colorado’s rapidly expanding quantum innovation ecosystem. Each seminar brings leading quantum scientists, entrepreneurs, and technologists from around the world to campus, creating a rare forum where students, researchers, and industry partners engage directly with the people and ideas shaping the future of quantum technology.

More than a research showcase, the series sparks collaboration, inspires emerging talent, accelerates workforce readiness, and strengthens Colorado’s role as a national leader in quantum science and commercialization. This event continues that tradition—bringing the community together to explore new breakthroughs, exchange perspectives, and advance the region’s quantum momentum.

The Department of Biochemistry invites professors and scientists from other universities and institutes to present seminars at the University of Colorado Boulder throughout the academic year. These seminars provide an opportunity for faculty and students to learn about exciting current research.

For the last quarter century, experiments at Brookhaven National Laboratory’s  Relativistic Heavy Ion Collider and the LHC at CERN have measured extremely high-energy heavy-ion collisions with the hope of producing the Quark Gluon Plasma (QGP) and extracting its properties. The success of this mission depends critically on combining careful, detailed and thorough measurement with complex multi-component theoretical simulations. I will first review how specific bulk properties are illuminated by specific experimental observables. I will then show how the comparison of these large heterogeneous data sets with computationally expensive models built on high-dimensional model-parameter spaces are rigorously constraining these properties through state-of-the-art Bayesian analysis. The extracted equation of state and chemical compositions are found to be consistent with lattice gauge theory. Other properties, which are not so well calculated on the lattice, such as the opacity and emissivity of QCD radiation, the diffusivity of both light and heavy quarks, and the viscosities have also been extracted. I will review where these determinations currently stand and how well they substantiate the claim of having produced the QGP in the laboratory. 

The Department of Biochemistry invites professors and scientists from other universities and institutes to present seminars at the University of Colorado Boulder throughout the academic year. These seminars provide an opportunity for faculty and students to learn about exciting current research.

As educators, we would like to prepare our students for 21st century physics careers. Overall, to ensure all students will become successful scientists, physics departments need to be able to provide evidence to make sure that we are reaching these goals. The field of Physics Education Research has made major contributions to various educational practices and materials to reform instruction in order to recruit and retain more students. However, while many research-based instructional strategies in physics have continued to advance, reform in undergraduate physics assessment tools has had limited space in these conversations. In this talk, I will motivate the need for the next generation of physics assessment tools and present a few projects that my physics education research lab at Michigan State University has been working on. In particular, I will discuss our efforts to build a more diverse set of tools to use within our classrooms in order to better understand our students’ learning as well as how we can best support them throughout their time in higher education.

Explore physics and quantum-related research through student showcases and poster sessions. Hear from industry executives Safy Fishov (AMD) and Billy Landuyt (ExxonMobil), and network with engineers from AMD. Food will be provided!

Visit the Research Expo website to RSVP or Register to present a poster:

• Register to present a poster by March 22.
• RSVP to attend by April 3.

The Department of Biochemistry invites professors and scientists from other universities and institutes to present seminars at the University of Colorado Boulder throughout the academic year. These seminars provide an opportunity for faculty and students to learn about exciting current research.

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.

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.

The Department of Biochemistry invites professors and scientists from other universities and institutes to present seminars at the University of Colorado Boulder throughout the academic year. These seminars provide an opportunity for faculty and students to learn about exciting current research.

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.

TBA

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.

The Department of Biochemistry invites professors and scientists from other universities and institutes to present seminars at the University of Colorado Boulder throughout the academic year. These seminars provide an opportunity for faculty and students to learn about exciting current research.

TBA

TBA