* denotes the organizer responsible for participant diversity in the workshop

May 25 – September 14
Individual Research

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. Click here for more information.

May 25 – September 14
Working Group

Working groups of between two and six physicists are encouraged. Click here for more information.

May 25 - June 15
Dwarf Galaxies as Cosmological Probes
Elena D'Onghia, University of Wisconsin
Mike Boylan-Kolchin, University of Maryland
Alyson Brooks, Rutgers University
Marla C. Geha, Yale University
Julio Navarro, University of Victoria
Beth Willman, Haverford College

Recent wide-field surveys have revolutionized our understanding of the Local Group of Galaxies. The Sloan Digital Sky Survey, in particular, has more than doubled the number of known dwarf galaxies orbiting the Milky Way and revealed a new population of ultrafaint dwarf satellites. At the same time, advances in computational cosmology have led to improved predictions for the properties of the smallest dark matter halos that host dwarf galaxies in the current paradigm of structure formation, the Lambda Cold Dark Matter model.

The simultaneous progress in the modeling and observing fronts has transformed dwarf galaxy studies into powerful probes of both the prevailing cosmological paradigm and of our understanding of galaxy formation. Locally, dwarfs trace the extreme faint end of the galaxy formation process, while at high redshift they seem to play an important role in the reionization of the Universe. Making explicit connections between the high and low redshift Universe holds the promise of validating or challenging the current cosmological paradigm of structure formation on small scales.

This Aspen Summer workshop will bring together experts in Galactic astronomy, cosmology and stellar astrophysics in order to promote collaborative efforts across theoretical, computational and observational disciplines. By fostering discussionsn and interactions between theorists and observers, we aim to help to set the scene for the exploitation of current and future surveys, including GAIA, and the Large Synoptic Survey Telescope.

May 25 - June 22
Modern Trends in Quantum Magnetism
Andrey Chubukov, University of Wisconsin
Roderich Moessner, Oxford University
Satoru Nakatsuji University of Tokyo
Natalia Perkins, University of Wisconsin
Oleg Tchernyshyov, Johns Hopkins University

Much of recent progress in modern condensed matter has been stimulated by important advances in the field of quantum magnetism. Notable examples of systems in which magnetism plays a crucial role include transition-metal compounds and heavy-fermion intermetallic compounds, where strong electron correlations lead to emerging collective properties and various novel behaviors. The important role in the understanding of these strongly correlated electron systems is played by the appearance of new low-energy spin models and development of powerful field theoretical approaches and advanced computational techniques allowing to study these models. This workshop will provide a broad overview of the latest results in quantum magnetism bringing together experimental and theoretical condensed matter physicists. During the workshop, we plan to discuss a range of topics including (i) Novel ground states of matter and excitations, (ii) Frustrated magnetism, (iii) Field theories of itinerant magnetism, (iv) Emergent gauge fields, and (v) Interplay of disorder and interactions.

June 1 - June 22
Bacteria Meet Physics II
Thierry Emonet, Yale University
KC Huang, Stanford University
David Nelson, Harvard University
Sima Setayeshgar, Indiana University
Ned Wingreen, Princeton University

Rapid technical progress and recent discoveries in molecular biology have brought biologists face-to-face with the importance and challenge of understanding emergent physical phenomena in living cells. Nowhere is this more evident than in the study of bacteria, where fast generation times, tractable genetic systems, a wealth of biochemical probes, novel imaging approaches, and the availability of complete genomes for hundreds of species have allowed dramatic progress in characterizing cellular components and their basic interactions. However, biologists have found that this characterization is generally inadequate to formulate a full understanding of cellular processes. This “understanding gap” points to the presence in cells of biophysical phenomena, often subtle, complex, and intrinsically out of equilibrium, that emerge from the multiple interactions of cellular components. Over evolutionary time, cells have exploited and interwoven these biophysical effects to optimize the function of their systems. For physicists, helping biologists to understand how cells use physics is not only a challenge but also an opportunity: billions of years of “experiments” in biophysics are packed into every cell. This workshop will addressing three broad areas where collaboration between physicists and bacteriologists have and continue to be highly productive: (1) intracellular organization, dynamics, and mechanics; (2) principles of information transmission and decision making; and (3) principles of nonequilibrium biophysics.

June 8 - June 29
Ultra-Compact Binaries as Laboratories for Fundamental Physics
Paul Groot, Radboud University Nijmegen
Ilya Mandel, University of Birmingham
Enrico Ramirez-Ruiz, University of California, Santa Cruz
Stephan Rosswog,Stockholm University

Ultra-compact binaries with orbital periods shorter than one hour are central to understanding such disparate phenomena as type Ia supernova and short gamma-ray burst explosions; they serve as laboratories for studying the physics of accretion, which produces the bulk of high-energy radiation in the Universe; and they are spectacular probes of the extreme physics at high energy and high density, being strong gravitational-wave sources. Recent progress in observations of ultra-compact populations ranges from a revolution in the discovery of detached white dwarf binaries to observations of gamma-ray pulsars. The coming decade holds enormous promise for further study of ultra-compact binaries, due to the advent of large wide-field and variability surveys to find new systems, efficient optical and near-IR spectrographs combined with large telescopes to allow detailed characterization of their properties, and the imminent advent of gravitational-wave astronomy, which will allow studying these populations in unprecedented detail. On the theoretical front, detailed modeling of the evolution of binaries, the onset of mass transfer and the merger process itself relies on further developing relativistic numerical methods, and combining hydrodynamics with radiation and magnetic interaction. The goal of this workshop is to bring together experts in binary evolution, stellar evolution, accretion processes,gravitational radiation, and radio, optical and X-ray astronomy in order to promote collaborations between these groups.

June 15 - July 6
Fast and Furious: Understanding Exotic Astrophysical Transcients
Joshua Bloom, University of California, Berkeley
Ryan Foley, University of Illinois
Suvi Gezari, University of Maryland
Daniel Kasen, University of California, Berkeley
Alicia M. Soderberg, Harvard University

Over the last decade, with the implementation of large, systematic, digital-image supernova searches, astrophysicists have begun to discover many astrophysical transients that do not fall into the traditional supernova classes. About a dozen new types of “exotic” or “peculiar” transients were found lurking in the shadows. These are observationally diverse events; some are 100 times fainter than typical supernovae, with durations of a few days instead of weeks (“Fast”), while others are 100 times brighter than typical supernovae and can last for years (“Furious”). Currently, discovery is outpacing understanding. This workshop aims to bring together researchers with diverse backgrounds and varied expertise to deepen our physical understanding of the heterogeneity of exotic transients, and to draw connections between classes. By bridging the current gap between data and theory, participants will have the opportunity to develop new theories and observing strategies, necessary preparations for the coming era of Advanced LIGO and LSST.

June 22- July 20
Connecting Flavor Physics with Naturalness: from Theory to Experiment
Roni Harnik, Fermi National Laboratory
Gudrun Hiller, Technical University of Dortmund
Graham Kribs, University of Oregon
Jure Zupan, University of Cincinnati

The past year has seen remarkable progress in the discovery and in scrutinizing the properties of a particle consistent with a Higgs boson. Electroweak symmetry breaking appears to be well described by a weakly-coupled sector with properties that are broadly consistent with the Standard Model. From the perspective of flavor physics, the LHC and Tevatron data provide new clues for flavor physics by measuring how the Higgs couples to fermions. From the perspective of electroweak symmetry breaking and Higgs physics, these new data provide new clues for the naturalness problem.
The aim of the workshop is to bring together experts to study flavor physics, and the origins of flavor, and see what impact this has on the naturalness problem of the Higgs sector and vice versa. Given the various experiments dedicated to flavor physics that are ongoing or planned, combined with the LHC data on Higgs physics, summer 2014 will prove to be an opportune moment to analyze the theory/experiment interplay for flavor and naturalness.

July 6 - August 3
Emergent Spacetime in String Theory
Donald Marolf, University of California, Santa Barbara
Joseph Polchinski, University of California, Santa Barbara
Eva Silverstein Stanford University

General arguments from black hole quantum mechanics suggest that spacetime must be holographic, emerging from degrees of freedom living on a lower dimensional space. AdS/CFT and other gauge/gravity dualities have given concrete examples of this. They provide at least a partial formulation of quantum gravity subject to special boundary conditions via a dual description which, intriguingly, makes no reference to the usual spacetime geometry. Many interesting results follow from this duality, including geometric realizations of supersymmetry breaking and confinement, new methods for finite density transport calculations, and the unitarity of black hole evaporation. But despite over 15 years of research, central questions involving the duality are still far from understood. These include the particular manner in which the bulk spacetime emerges from the dual gauge theory, whether the duality provides a complete and unique definition of the bulk theory, and how to best describe bulk degrees of freedom far from the boundary -- especially inside the horizons of black holes. This part of the duality appears particularly important in attempts to generalize it to backgrounds closer to the spacetime we observe, dominated by a positive cosmological constant today and with structure apparently seeded by quantum fluctuations during early universe inflation. Our program will address central problems on a broad front using a variety of methods including the study of entanglement entropy and its connection with spacetime geometry, various approaches to holography for de Sitter and other cosmological spacetimes, new insights from the black hole information paradox, and detailed analysis of concrete models such as higher spin gravity and string-theoretic constructions.

July 20 - August 10
Combining Probes in Cosmological Surveys
Sarah Bridle, University of Manchester
Scott Dodelson, Fermi National Laboratory
Masahiro Takada, Kavli Institute for the Physics and Mathematics of the Universe

The Lambda-dominated Cold Dark Matter paradigm successfully explains a broad range of cosmological observations including the recent Planck measurement of cosmic microwave background anisotropies. However, the success is only phenomenological in that the model requires introducing new unknown physics in the form of inflation, dark matter and dark energy or modified gravity. Understanding the nature of this new physics is arguably the most tantalizing problem in cosmology today. Cosmological observations, such as galaxy surveys and cosmic microwave background experiments, offer the most promising way of making progress on these problems. The workshop will focus on learning even more about the new physics by combining the many probes made possible by these observations.

August 3 - August 31
Model Building in the LHC Era
Mu-Chun Chen, University of California, Irvine
Stuart Raby, Ohio State University
Michael Ratz, Technical University, Munich
Carlos Wagner, University of Chicago

The workshop will concentrate on the question of Higgs physics, as well as on models that provide a description of high energy physics phenomena beyond the one provided by the SM. It will bring together experts working on the various areas of particle physics model building and phenomenology (extensions of the standard model, neutrino, grand unified and string model building) to confront the theories with current experimental data from the LHC and other experiments, such as direct and indirect dark matter detection experiments, as well as discussing future searches.Present and future data from the LHC and other experiments may discover new physics beyond the SM and/or allow us to constrain this new physics. It will also help us to identify viable settings which are consistent with other requirements, such as those from flavor physics or cosmology. Guidelines for model building can come from more top--down scenarios such as grand unified theories, string compactifications and/or models with (warped) extra dimensions. We aim at a discussion of how to test such ideas at the LHC and other experiments, and possibly invent new ways of exploring physics beyond the standard model.

August 10 - September 7
Gauge Fields in Condensed Matter, Ultracold Atoms and Beyond
Victor Galitski, University of Maryland
Arun Paramekanti, University of Toronto
Daniel Podolsky, Technion
Ian Spielman, National Institute of Standards and Technology
Smitha Vishveshwara, University of Illinois

The physics of gauge fields spans energy scales ranging from trillions of Kelvin in particle physics to the scale of a few Kelvin for solids. Recent experiments on ultracold atomic gases have made remarkable breakthroughs in realizing synthetic magnetic fields and spin-orbit coupling for neutral atoms, pushing the energy scale to observe the physics of gauge fields down to the nano-Kelvin. Parallel developments in condensed matter physics include the discovery of new states of quantum condensed matter --- topological insulators, quantum spin liquids, and Chern insulators --- in which spin-orbit coupling and emergent dynamical gauge fields play an important role. Particles such as the famous Higgs boson, which play a crucial role in gauge theories of elementary particles and in condensed matter physics, have also recently been detected in experiments on the atomic Bose Hubbard model. Such emergent gauge fields also appear in itinerant magnets, accompanying the formation of exotic skyrmion textures. The aim of this workshop is to bring together leading theorists and experimentalists in the field of ultracold atomic gases and condensed matter physics in order to foster an exchange of ideas. Given the rapid developments in these areas, both in ultracold atoms and solid-state physics, such an interdisciplinary workshop would be extremely timely and have a great impact in setting directions for future research.

August 10 - August 31
Many-Body Quantum Systems Far from Equilibrium
Uwe Bovensiepen, University of Duisburg-Essen
Andew Daley, University of Pittsburgh
James Freericks, Georgetown University
Marcos Rigol, Pennsylvania State University
Joerg Schmiedmayer, TU-Wien

Despite the great progress made over the last 50 years in understanding quantum many-body systems in equilibrium, their dynamics far from equilibrium has remained relatively unexplored until quite recently. This results in part from the fact that we do not yet have a unified theoretical framework for non-equilibrium systems that is comparable to well-established concepts of universality in equilibrium systems, and in part because it was previously very difficult to probe nonequilibrium relaxation processes in experiments. This picture has changed rapidly in the last few years as great progress has been made in the AMO and Condensed Matter communities, both in terms of new experiments that give access to dynamics on fast timescales and in clean environments, and also in terms of theoretical advances in describing these processes. The goal of this program is to bring together a core of theorists and experimentalists from the AMO and Condensed Matter communities, as well as a variety of researchers from other fields. We will discuss recent developments in the understanding of many-body quantum dynamics, with an emphasis on the advances in theoretical formalisms and experimental approaches that have made those developments possible. By stimulating the sharing ideas between these separate communities, and bringing these communities in contact with researchers studying out-of-equilibrium processes in other subfields, we aim to accelerate the development of an understanding of far from equilibrium quantum dynamics.

August 24 - September 14
The Galaxy-Halo Connection Across Cosmic Time
Andreas Berlind, Vanderbilt University
Frank Van Den Bosch, University of Utah
Jeremy Tinker, New York University
Risa Wechsler, Stanford University
Andrew Zentner, University of Pittsburgh

August 31 - September 14
Radiation Driven Outflows in Stars and Quasars
Janet Drew, University of Hertfordshire
Martin Elvis, Harvard-Smithsonian Center for Astrophysics
Fred Hamann, University of Florida
Norman Murray, University of Toronto
Nolan R. Walborn, Space Telescope Science Institute

Radiation pressure operates in a wide range of astrophysical environments from comets to quasars. Both the phenomenology and the physics involved is complex and is dominated by electron scattering and atomic line driving in ionized environments. Understanding line driving and closely associated problems are subjects of active interest in several distinct fields. This workshop concentrates on the best-studied areas: stellar winds in hot stars and disk winds in compact binaries, and quasars. These separate fields are a classic case of long-suspected, but little-explored physical commonalities. For example, understanding of O-star wind physics is quite advanced, while that of quasars is less so and might benefit from the former. Conversely, quasar phenomena span a wider range of physical conditions and so may well illuminate the key physics to apply to current issues in massive stellar winds. By bringing the best observers and theorists in each field for extensive discussions this workshop aims to establish collaborations across research areas. To enable this no session will be exclusively focused on stars, CVs or on quasars, but will address a single physical problem common to both.