Kiosk 3

The behavior of the doped Hubbard model at low temperatures is a central problem in modern condensed matter physics, with relevance to correlated materials such as cuprate superconductors. Despite extensive computational studies, many open questions remain on its low-temperature phase diagram, motivating its study through quantum simulation with ultracold fermionic atoms in optical lattices. Here, leveraging a recent several-fold reduction in experimental temperatures, we report the first direct experimental observation of the pseudogap metal in the Hubbard model. These measurements are enabled by a novel, efficient spectroscopic technique with which we resolve the opening of a partial gap, which we further correlate with a thermodynamic anomaly in the equation of state that emerges at low temperatures. Our results partially characterize the pseudogap regime and hint at a link between the pseudogap and charge order, which can be probed in future work. Furthermore, these results demonstrate the utility of quantum simulation in addressing frontier problems in correlated electron physics.

Abstract: The discovery of thousands of planets orbiting stars beyond the solar system has fundamentally shifted our view of Earth’s place in the Universe, has captivated the public imagination, and has transformed research priorities in astrophysics. We are now actively searching for atmospheres on temperate, terrestrial planets, and are developing the technical tools to find and characterize “Earth-2.0”. The goal of understanding the frequency and diversity of habitable (and inhabited) planets requires a `full system approach’ where we bring to bear multiple techniques for exoplanetary observation and a detailed understanding of the evolving stellar environments in which they live.

In this talk, I will present an overview of the multiple paths in our search for inhabited planets, from current efforts to find temperate planets with stable atmospheres around red dwarf stars to future detection of true Earth-Sun analogs with NASA’s upcoming Habitable Worlds Observatory (HWO). I will summarize recent progress and open questions in understanding the key stellar environmental variables that influence exoplanet atmospheres, focusing on observational and experimental work to characterize the high-energy photon and particle radiation that dominates atmospheric escape on rocky planets. I will conclude with a short overview of the upcoming HWO mission, current opportunities for the community to engage with the mission development, and the path to launch in the ~2040 timeframe.

Over the last 20 years, we have discovered that we live in a molecular Universe: A Universe with a rich and varied organic inventory; A Universe where molecules are abundant and widespread; A Universe where molecules play a central role in key processes that dominate the structure and evolution of galaxies. A Universe where molecules provide convenient thermometers and barometers to probe local physical conditions. Understanding the origin and evolution of interstellar and circumstellar molecules is therefore key to understanding the Universe around us and our place in it and has therefore become a fundamental goal of modern astrophysics. 
The field is heavily driven by new observational tools that have become available over the last 20 years; Ground-based and space-based observatorieshave opened up the IR and sub-millimeter window. In particular, spectroscopic observations with NASA’s James Webb Space Telescope (JWST) reveal adiversity of aromatic species in the Universe and a rich chemistry drivingmolecular complexity.
Our progress in understanding the Molecular Universe is greatly aided by a close collaborations between astronomers, molecular physicists, astrochemists, spectroscopists, and physical chemists who work together in loosely organized networks. In this talk, I will sketch the progress that we have made after the launch of JWST and outline some of the challenges that are facing us. The focus will be on understanding the role of aromatic species in the organic inventory of regions of star and planet formation that may well have contributed to the prebiotic roots to life.

Engineering heterogenous multicellular tissue with native complexity remains one of the holy grails of regenerative medicine and basic biological research. As success in this regard would yield powerful bioengineered constructs useful in functional transplantation, high-throughput drug screening, and fundamental biology investigation, research efforts in our lab have centered around developing and implementing tools to spatiotemporally customize living cell function both from the “outside–in” and from the “inside–out”. In this talk, I will discuss some of our group’s recent successes in reversibly modifying the chemical and physical aspects of synthetic cell culture platforms with user-defined and grayscale control, regulating cell-biomaterial interactions through user-programmable Boolean logic, engineering microvascular networks that span nearly all size scales of native human vasculature (including capillaries), irreversibly photoassembling bioactive proteins within living cells, and driving biomolecular condensate formation using de novo-designed proteins. Results will highlight our ability to modulate intricate cellular behavior including stem cell differentiation, protein secretion, and cell-cell interactions in 4D. 

The year 2024 was a breakthrough year towards the development of a nuclear optical clock, with three experiments reporting success in the laser spectroscopy of the lowest nuclear excited state of 229-Th. The highest accuracy was achieved at JILA via direct frequency comb spectroscopy of this, previously elusive, nuclear state. This success is the result of several decades of effort to precisely determine the transition energy and a first step towards nuclear precision spectroscopy and the development of a nuclear frequency standard of extremely high accuracy.

In this talk I will provide an overview over the history of 229-Th that has culminated in this success. Further, I will discuss the remaining efforts and challenges. Finally, I will introduce the investigations underway within the framework of the BMFTR-funded project “NuQuant”.

TBA

The quantum 2.0 revolution is well underway, with a tantalizing future just over the horizon wherein computing, networking, sensing, and even time-keeping will be unimaginably more capable than they are today. The promise of this future hinges on the ability to control, entangle, and measure both individual qubits and large systems of them. Many of the most promising physical qubit systems being developed for these purposes are atomic in nature, i.e. trapped neutral atoms, trapped ions, and artificial atoms in crystals. These atomic qubits interact almost exclusively with visible or even UV photons, requiring incredibly precise phase, frequency, and amplitude conditioning of and modulation of those photons to control them. While these systems have advanced by leaps and bounds over the last decade by focusing on small-scale implementations with a few to a few thousand qubits using “tabletop” optical controls, all of them are now bottlenecked by the inability to scale these controls to the qubit counts required for true scientific, technological, and societal utility, which will require several orders of magnitude more qubits with no degradation in performance.

In this talk, I will describe my group’s past, present, and future efforts to clear this bottleneck by hijacking the most scalable manufacturing processes known to man—those used to manufacture complimentary metal-oxide semiconductor (CMOS) electronic integrated circuits—to make very large-scale optical control circuits. To do this, we have developed a novel photonic integrated circuit (PIC) architecture that uses integrated piezoelectric force actuators to deform dielectric waveguides made of common CMOS insulators: silicon nitride, silicon dioxide, and aluminum oxide. I will show that this piezo-optomechanical PIC architecture provides electronic control of all the necessary degrees of freedom for photons across the entire visible spectrum and far enough into the ultraviolet to address the most important qubit species. Critically, the PIC platform has high modulation bandwidth, works from room temperature to cryogenic temperatures, handles optical power up to (at least) several watts, and has low power dissipation, self-heating, and cross-talk, paving the way towards utility scale quantum information processing with atomic qubits.

Abstract: A new zoo consisting of dozens of heavy subatomic particles that contain more than three quarks and antiquarks have been discovered beginning in 2003.  Although they must be described by the fundamental quantum field theory QCD, the pattern of these exotic heavy hadrons remained unexplained for more than 20 years.  I will present a simple proposal for the pattern based on the Born-Oppenheimer approximation for QCD.  There are simple calculations in lattice QCD that would corroborate the pattern.  The quantitative description of these exotic heavy hadrons requires the diabatic representation of the Born-Oppenheimer approximation, which has led to dramatic advances in atomic and molecular physics in recent decades.

TBA

NASA science missions are often complex systems of systems, involving various stakeholders, including the United States’ Congress. To ensure a clear and concise communication of expectations, requirements, and constraints, NASA has adopted the Science Traceability Matrix (STM). STM provides a logical flow from the decadal survey to science goals and objectives, mission and instrument requirements, and data products. STM serves as a summary of what science will be achieved and how it will be achieved, with a clear definition of what mission success will look like. In this seminar, I will present the STM from the Parker Solar Probe (PSP), including requirements relating to the plasma instrument for which I am a co-investigator. I will describe how our team used the STM to map the mission’s top-level requirements to mission success criteria and helped to eliminate any single point of failure that could end the mission prematurely. I will then present my own research on magnetic switchbacks in the PSP magnetic and plasma observations and their role in solar wind acceleration and heating. I will conclude the seminar by discussing how my research on the temporal evolution of switchbacks in the solar wind led to a new STM, and helped to chart a multidisciplinary path to designing a ground-breaking science mission concept, titled Space Weather Investigation Frontier (SWIFT), with the potential to improve space weather forecasting lead times by up to 40%.

TBA

From planting crops to making trains run efficiently, clocks have been an important tool throughout most of human history. Atomic clocks, based on quantum-mechanically-defined transitions in atoms, are currently the most accurate realizations of the second and underlie important technologies such as the global positioning system (GPS) and high-speed communications. This lecture will describe how atomic clocks work and their history, with a focus on compact clocks and the applications in which they are used.

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

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.