Physicists are encouraged
to apply as individual researchers to work
on their own projects for up to five weeks
at any time during the summer. We provide
a serene atmosphere to complete work. The
individual researcher may also choose to
attend any workshop meetings or chat with
other scientists in residence in addition
to working on his or her own research.
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Cosmic Ray Feedback in Galaxies and Galaxy Clusters
Christoph Pfrommer, Leibniz Institute for Astrophysics
Mateusz Ruszkowski, University of Michigan
*Ellen Zweibel, University of Wisconsin
Understanding the processes underlying galaxy formation is one of the most important challenges in astrophysics. Unresolved questions include the disconnect between the short time scale of gas collapse on small scales and the long time scale for galaxy evolution, as well as the mechanism responsible for ejecting mass, momentum, and energy out of galaxies (or preventing their infall) in a way that matches the observed scaling relations. Recent progress in the field of astrophysical feedback strongly suggests that relativistic particle populations called cosmic rays may play a crucial role in controlling these processes in and around galaxies and galaxy clusters. However, the strength of cosmic ray feedback depends very sensitively on the dynamical coupling of cosmic rays to the plasma, a complete understanding of which will require novel plasma physics insights. Connecting detailed simulations to multi-frequency and multi-messenger observations will be of paramount importance for elucidating the underlying physics. Hence, the goal of this workshop is to bring together an interdisciplinary group of scientists studying plasma physics, cosmic ray propagation in the Milky Way, high-energy astrophysics (embracing radio, X-ray, and gamma-ray astronomy), galaxy formation, and evolution of galaxy clusters in order to learn from each other, facilitate collaborations among the participants, and advance the field into an era of predictive galaxy formation.
26 - June 23
Fundamental Physics in the Era of Big Data
and Machine Learning
*Gregor Kasieczka, Universität Hamburg
Francois Lanusse, CNRS
Siddarth Mishra-Sharma, Massachusetts Institute of Technology
**Lina Necib, Massachusetts Institute of Technology
David Shih, Rutgers University
Large data sets have overtaken most fields of physics, from the smallest scales of high energy physics to the largest scales of astronomy and cosmology. Experimental developments on all fronts, from current detectors including the LHC, the Gaia space mission, and LIGO to upcoming experiments such as the Rubin Observatory and Square Kilometer Array (SKA) require a redefinition of our approach to physics in order to fully exploit such advancements. In parallel, the field is in the midst of a revolution in machine learning (ML) and artificial intelligence (AI). Applications of powerful new AI/ML techniques to Big Data promise to open a never-before-seen window into the essential questions of fundamental physics, such as the search for physics beyond the Standard Model, the particle nature of Dark Matter, the cosmological formation of structure, and the history of the Universe. This workshop will aim to bring together experts in AI/ML and Big Data across a wide variety of subfields of fundamental physics, as well as AI/ML researchers from industry and academia who are potentially interested in physics applications. The primary goal of the workshop will be to provide unique opportunities for researchers to exchange ideas, develop new techniques, and cross-pollinate solutions to common problems posed by Big Data across the different domains of fundamental physics.
June 2 - June 30
The Microscopic Origin of Black Hole Entropy
Vijay Balasubramanian, University of Pennsylvania
*Javier Magan, Instituto Balseiro
Gustavo J Turiaci, University of Washington
Herman Verlinde, Princeton University
Bekenstein and Hawking proposed, on the basis of general relativity and quantum mechanics in curved spacetimes, that black holes behave as thermodynamic objects, and carry a large and finite entropy proportional to its event horizon area in Planck units. An outstanding question in theoretical physics in the intervening decades has been to explain the origin of this universal formula and its implications to a theory of quantum gravity. Recent years have witnessed groundbreaking progress towards this goal from different corners of the field such as String Theory (a theory of quantum gravity), quantum information, quantum chaos, the fuzzball program and soft modes in gravity. In particular the gravitational path integral has been a key tool in combining much of these progress. It is then timely and important to bring together these different communities, so that recent discoveries can be shared and critiqued, and next steps can be envisioned. The purpose of this workshop is to accomplish this task.
16 - July 7
Quantum Matter Through the Lens of Moiré Materials
Philip Kim, Harvard University
Eslam Khalaf, Harvard University
Jed Pixley, Rutgers University
*Raquel Queiroz, Columbia University
Experimental advances in the ability to grow, isolate, twist, and stack two-dimensional materials have ushered in a new era in condensed matter physics. The moire patterns formed by stacking and twisting two lattices bring an immense tunability of quantum phases to two-dimensional materials, which are rapidly becoming the most exciting playground for the observation of exotic correlated phenomena. The goal of this workshop is to bring together current and future leaders in condensed matter physics, both experimental and theoretical, to discuss the rapid development of this novel class of quantum matter. An important theme of the workshop will focus on connections to other subfields to find creative solutions to open problems. The program will focus on pressing theoretical and experimental questions, such as the nature of the correlated states and the importance of topology, novel experimental techniques, pathways to the realization of long-sought quantum phases, and the identification of new twisted systems yet to be explored.
23 - July 21
Leveraging the Lepton Sector
as a Probe for New Physics
Simon Knapen, Lawrence Berkeley National Laboratory
*Shirley Li, University of California Irvine
Maxim Pospelov, University of Minnesota
Diego Redigolo, INFN Florence
Much of the expected progress in particle physics for the next few decades will come from experiments that leverage the lepton sector, include low-energy electron and muon beams, possible next-generation high-energy lepton colliders, precision measurements of the electron and muon magnetic dipole moments, searches for CP violation in the lepton sector and searches for dark matter with couplings to electrons. A wealth of new data related to the neutrino sector is also expected to become available, from long-baseline experiments to astrophysical and cosmological probes. This workshop will explore these physics opportunities and aims to impact the ongoing and future experimental programs.
July 7 - August 4
Probing Collective Excitations in Quantum Matter
by Transport and Spectroscopy
N. Peter Armitage, Johns Hopkins University
Cristian Batista, University of Tennessee
Johannes Knolle, Technical University of Munich
*Natalia Perkins, University of Minnesota
In recent years, significant progress has been made in understanding strongly correlated quantum materials, with a particular focus on topological systems like quantum spin liquids. These achievements in understanding have been made possible by remarkable developments in both materials science and experimental techniques. In particular, improvements in both traditional experimental tools (e.g., inelastic neutron scattering, Raman scattering, resonant X-ray scattering, and ultrasound spectroscopy) and the introduction of innovative techniques such as 2D coherent THz spectroscopy and sophisticated noise experiments have advanced studies of quantum matter to qualitatively new levels of insight. While our theoretical understanding of ground state properties, including their classification, has likewise seen significant improvements, there remains a relative gap in our comprehension of experimentally accessible dynamical response functions. This workshop aims to bridge this gap by fostering theoretical advancements in understanding the dynamics of collective excitations. We will explore novel approaches for computing dynamical response functions in highly entangled systems, providing insights into various spectroscopic techniques, including nonlinear responses. We invite applications from scientists interested in this research and hope that through collaboration we will advance our understanding of complex quantum phenomena and their manifestations in experimental settings.
July 21 - August 18
Physics of Biological Data Analysis
*Marianne Bauer, Delft University of Technology
Anne-Florence Bitbol, École Polytechnique Fédérale de Lausanne
Ilya Nemenman, Emory University
Greg Stephens, Vrije Universiteit Amsterdam
The amount and quality of biological datasets available is fast increasing. This holds at the molecular and cellular scales (gene sequence and expression data), but also at larger ones (populations and communities of cells, behavior of one or multiple animals). Making sense of these extraordinarily rich datasets calls for new inference and interpretation methods, and ultimately new theory. Since microscopic theories of biology may not provide insight on larger scales, data-driven approaches play an integral role in biophysics, for example guiding us to discovering new physical laws.
Various analysis approaches inspired by statistical physics and by machine learning are currently being developed. They range from fitting models to model-free analysis, and include supervised and unsupervised approaches. Recent advances in machine learning offer powerful new methods. For instance, some deep neural networks capture very well the rich structure of biological sequence data. Physics-based concepts play important parts in these analysis approaches, including deep learning ones. In turn, these models provide insight on biophysical phenomena.
This workshop will bring together scientists modeling biological data, performing and analyzing data-rich experiments, and those who are interested in developing, using and understanding new data analysis methods, such as deep learning. We will compare approaches, discuss successes and failures in data analysis, and reflect on future directions.
August 4 - August 25
Multi-messenger Transients from Binary Mergers
& Stellar Explosions
Ore Gottlieb, Flatiron Institute
Raffaella Margutti, University of California Berkeley
*Enrico Ramirez-Ruiz, University of California Santa Cruz
Irene Tamborra, Niels Bohr Institute
The first joint gravitational wave and electromagnetic detection of the binary neutron star GW170817 marked the dawn of the multi-messenger era with GWs. This watershed event opened a new window to study phenomena such as heavy element nucleosynthesis, black hole formation, the Universe's expansion rate, the equation of state of dense matter, and the intricate dynamics of relativistic jets. These profound inquiries have reignited interest in investigating similar physical processes at play in black hole-neutron star mergers and core-collapse supernovae. This endeavor necessitates the development of predictive models in anticipation of forthcoming observations in 2024 by LIGO-Virgo-KAGRA, Rubin Observatory, and future observation campaigns, that will transform the field of high-energy astrophysics transients. The primary goal of this workshop is to bring together physicists with diverse backgrounds in both theoretical and observational expertise within the domains of electromagnetic, gravitational wave, and particle emissions. Collectively, they will engage in collaborative efforts to identify and investigate pathways for tackling the pivotal scientific questions at the core of this rapidly evolving field.
August 11 - September 8
Accretion Physics in the Era of JWST
Misty Bentz, Georgia State University
Christine Done, Durham University
Martin Elvis, Harvard Smithsonian Center for Astrophysics
*Guido Risaliti, University of Florence
The accretion-powered growth of supermassive black holes releases enormous amounts of gravitational potential energy, powering the activity seen in quasars and active galactic nuclei. This power is emitted as radiation across the electromagnetic spectrum, transforming the darkest objects in the Universe into the brightest, and is also emitted in kinetic components such as winds and jets. Together these feedback effects inject some fraction of the accretion power into the host galaxy, controlling its growth via star formation over cosmic time. While this outline captures our current understanding, fundamental unanswered questions remain such as "What is the nature of the accretion flow?" and “How can the accretion process grow such large black hole masses in such a short time after the Big Bang?” With the December 2021 launch of JWST, an enormous discovery space has been opened in wavelength, sensitivity, and angular resolution for studying massive accreting black holes across cosmic time. We will bring together experts in theory, observations, and computational modeling for discussion of the state of the art in our understanding of the AGN phase and the accretion process as well as collaborative planning for future exploration with the new tools and capabilities that JWST provides. Synergies with Euclid, Roman, and other new facilities will also be a key part of the Workshop.
18 - September 15
Tightening the Gap Between Scattering Amplitudes
and Events at the LHC at Higher Orders
Fernando Febres Cordero, Florida State University
Bernhard Mistlberger, SLAC
*Peter Skands, Monash University
The simulation of high-energy hadron collider events is a necessary task to achieve the scientific goals of the current run at the LHC and its future high-luminosity upgrade HL-LHC. Experimental collaborations rely on Monte Carlo event generators which combine a large amount of tools needed for the task. In recent years great advances have been made to improve in these generators the description of the hard-interaction process by including higher-order QCD corrections. This workshop will bring together leading experts in perturbative calculations, parton-shower Monte Carlo frameworks, and state-of-the-art ML techniques to develop the next generation of tools for precision phenomenology at hadron colliders. The goal is to create tools that will enable theorists to make percent-level predictions for a wide variety of observables at the LHC.
August 25 - September
Toward a Holistic Understanding of the Multi-scale,
Multiphase Circumgalactic Medium
Hsiao-Wen Chen, University of Chicago
Claude-Andre Faucher-Giguere, Northwestern
*S. Peng Oh, University of California Santa Barbara
Gwen Rudie, Carnegie Observatories
The CGM is host to a multitude of physical processes critical to the formation and evolution of galaxies. On large scales, these include inflows from the cosmic web (~Mpc) that fuel star formation and outflows produced by galactic feedback. On small scales, multiphase gas gives rise to a spectrum of cold gas structures going down to sub-pc scales. However, the mutual interplay between small-scale structure and large-scale dynamics remains a key open question. A major challenge is that the enormous range of physical scales and physical processes involved means that this problem cannot be solved by brute-force computation. Instead, we must combine insights from different approaches, including cosmological simulations, well-resolved idealized simulations (such as how cold clouds exchange mass, momentum, and energy with a hot phase), analytic modeling, and multi-wavelength observations. This workshop will bring together theorists and observers with different perspectives to exchange ideas, stimulate innovative projects through extended discussions, and seed new collaborations to advance the field. Key themes will include the physics of multiphase gas, connecting small scales and large scales, and how existing and new observations can constrain CGM physics.