News and Events
The properties of a material are often thought to be determined primarily by the elements from which it is made. But what happens when the geometry of a crystal lattice itself becomes a source of new quantum phenomena? In this talk, I will explore this question through the physics of kagome metals—materials whose atoms form a network of corner-sharing triangles. The kagome lattice provides a remarkable example of how geometry can reshape the electronic landscape of a metal. Quantum interference between electronic pathways produces nearly flat electronic bands, while the same lattice can host Dirac-like band crossings and van Hove singularities, where the density of electronic states becomes strongly enhanced. These features can dramatically amplify the effects of interactions between electrons, creating an unusually rich environment for collective quantum phenomena. Kagome materials have consequently emerged as a platform for studying charge-density waves, magnetism, unconventional superconductivity, nematicity, anomalous Hall responses, and other forms of intertwined and potentially topological order. I will discuss how these ideas emerge from the electronic structure and how they manifest experimentally in real materials. In particular, I will highlight recent work from my group using the experimental technique of angle-resolved photoemission spectroscopy (ARPES) to directly visualize the electronic states of several kagome metals and to follow their evolution across the various phase transitions. These experiments reveal an intimate connection between the underlying band structure and the collective behavior of the electrons, while also highlighting the ways in which real materials can depart from simple theoretical pictures.
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Selected Publications
Passive radiators are notoriously difficult to characterize because one cannot effectively assess their mechanical parameters with loudspeaker electrical impedance techniques and no motors. This paper discusses the details of passive radiator and dynamic loudspeaker driver parameter measurements through practical experiments conducted with a plane wave tube, the two-microphone transfer function technique, and the two-load method to remove the need for an ideal anechoic termination. A previous theoretical paper demonstrated how normal-incidence transmission losses through these devices in an anechoically terminated tube could yield their mechanical and electrical parameters [Leishman and Anderson, J. Acoust. Soc. Am. 134(1), 223–236 (2013)]. The mechanical parameters follow from an open-circuit transmission loss condition, whereas a driver's electrical parameters follow from an additional closed-circuit condition. This paper presents several experimental results and compares extracted parameters to those derived from electrical impedance measurements and destructive methods. In addition to other parameters, the masses of diaphragm assemblies show favorable agreement. The presented techniques effectively assess passive radiator parameters without employing active driver configurations and then removing their motors, which changes the measured properties. PACS numbers: 43.38.Ja, 43.20.Ye, 43.20.Mv, 43.55.Rg
Volume 3 of the FCC Feasibility Report presents studies related to civil engineering, the development of a project implementation scenario, and environmental and sustainability aspects. The report details the iterative improvements made to the civil engineering concepts since 2018, taking into account subsurface conditions, accelerator and experiment requirements, and territorial considerations. It outlines a technically feasible and economically viable civil engineering configuration that serves as the baseline for detailed subsurface investigations, construction design, cost estimation, and project implementation planning. Additionally, the report highlights ongoing subsurface investigations in key areas to support the development of an improved 3D subsurface model of the region. The report describes the development of the project scenario based on the ‘avoid-reduce-compensate’ iterative optimisation approach. The reference scenario balances optimal physics performance with territorial compatibility, implementation risks, and costs. Environmental field investigations covering almost 600 hectares of terrain—including numerous urban, economic, social, and technical aspects—confirmed the project’s technical feasibility and contributed to the preparation of essential input documents for the formal project authorisation phase. The summary also highlights the initiation of public dialogue as part of the authorisation process. The results of a comprehensive socio-economic impact assessment, which included significant environmental effects, are presented. Even under the most conservative and stringent conditions, a positive benefit-cost ratio for the FCC-ee is obtained. Finally, the report provides a summary of the studies conducted to document the current state of the environment.
Protein function emerges from dynamic conformational changes, yet structure prediction methods provide only static snapshots. While AlphaFold3 (AF3) predicts protein structures, the potential for extracting dynamic information from its ensemble predictions has remained underexplored. Here, we demonstrate that AF3 structural ensembles contain substantial dynamic information that correlates remarkably well with molecular dynamics simulations (MD). We developed ChronoSort, a novel algorithm that organizes static structure predictions into temporally coherent trajectories by minimizing structural differences between neighboring frames. Through systematic analysis of four diverse protein targets, we show that root-mean-square fluctuations derived from AF3 ensembles can correlate strongly with those from MD (r = 0.53 to 0.84). Principal component analysis reveals that AF3 predictions capture the same collective motion patterns observed in molecular dynamics trajectories, with eigenvector similarities significantly exceeding random distributions. ChronoSort trajectories exhibit structural evolution profiles comparable to MD. These findings suggest that modern AI-based structure prediction tools encode conformational flexibility information that can be systematically extracted without expensive MD. We provide ChronoSort as open-source software to enable broad community adoption. This work offers a novel approach to extracting functional insights from structure prediction tools in minutes, with significant implications for synthetic biology, protein engineering, drug discovery, and structure–function studies.
We present ExoMiner++, an enhanced deep learning model that builds on the success of ExoMiner to improve transit signal classification in 2-minute TESS data. ExoMiner++ incorporates additional diagnostic inputs, including periodogram, flux trend, difference image, unfolded flux, and spacecraft attitude control data, all of which are crucial for effectively distinguishing transit signals from more challenging sources of false positives (FPs). To further enhance performance, we leverage multisource training by combining high-quality labeled data from the Kepler space telescope with TESS data. This approach mitigates the impact of TESS’s noisier and more ambiguous labels. ExoMiner++ achieves high accuracy across various classification and ranking metrics, significantly narrowing the search space for follow-up investigations to confirm new planets. To serve the exoplanet community, we introduce a new TESS catalog containing ExoMiner++ classifications and confidence scores for each transit signal. Among the 147,568 unlabeled TCEs, ExoMiner++ identifies 7330 as planet candidates (PCs), with the remainder classified as FPs. These 7330 PCs correspond to 1868 existing TESS Objects of Interest (TOIs), 69 Community TESS Objects of Interest (CTOIs), and 50 newly introduced CTOIs. 1797 out of the 2506 TOIs previously labeled as PCs in ExoFOP are classified as PCs by ExoMiner++. This reduction in plausible candidates, combined with the excellent ranking quality of ExoMiner++, allows the follow-up efforts to be focused on the most likely candidates, increasing the overall planet yield.
With the rapid growth and development of potential commercial fusion power plants, the urgency of building a skilled workforce is increasing. Therefore, it is necessary to train and educate early-career scientists and engineers to be able to work for current and future employment in fusion-related fields. In the Inertial Fusion Science and Technology (RISE) Hub, efforts are underway to address this urgency. Specifically in the RISE Hub, we train the next generation of “fusioneers” by involving them in every level of Hub activities. Here, we describe several training, outreach, and educational activities that are led by early-career scientists and engineers, graduate students, and postdoctoral researchers, under the supervision of Hub professionals. These activities educate and train students on key aspects of fusion systems, from the laser driver technologies to the target design, manufacturing, simulation, and validation. In addition, several of these initiatives are being supported by industry partners, national laboratories, and universities, facilitating the transition of knowledge between fusion experts and students. The goals of these outreach efforts led by the RISE Hub are not only to train and educate a skilled workforce but to grow young leaders and broaden their participation in developing commercial fusion power plants.
During the past few years, orbital rocket launches at Vandenberg Space Force Base (VSFB) have increased nearly ten-fold from twenty years ago. As such, there are renewed concerns about the effects of launch noise on threatened and endangered species with critical habitats within VSFB. This talk provides an overview of an interdisciplinary research program to measure and model launch and landing noise on Base and to study responses of two coastal birds, the western snowy plover and the California least tern. Short- and long-term effects are being studied, from changes in vocalization to nest success. This presentation discusses launch noise environments and findings to date.