2012 SUMMER
PROGRAM
* denotes the organizer
responsible for participant diversity in
the workshop
May 20 – June 10
Non-Gaussianity as a
Window to the Primordial Universe
Organizers:
Neal Dalal,
University of Toronto
Olivier Dore, JPL, NASA
Dragan Huterer,
University of Michigan
DongHui Jeong, Caltech
Marc Kamionkowski,
Caltech
Fabian Schmidt*, Caltech
Sarah Shandera,
Pennsylvania State University
Over the last 30 years
cosmological inflation has emerged as the
most popular scenario that explains the
origin of the primordial seed
fluctuations. While current measurements
from the cosmic microwave background (CMB)
and large-scale structure (LSS) confirm
that the spectrum of primordial
fluctuations is Gaussian to a remarkable
one part in a thousand, that bound is
still several orders of magnitude away
from testing primordial non-Gaussianity at
the level predicted by slow–roll
inflation, and about one order of
magnitude above the level expected from
non-linear post–inflationary processing of
the fluctuations. The contraints on
deviations from Gaussianity will improve
dramatically in the near future, driven
both by CMB and LSS data. A detection of
primordial non-Gaussianity would open a
new and extremely informative window on
the physics of inflation and the very
early Universe.
Maximizing the potential
of discovery for large new data sets, and
interpreting their results, are
challenging tasks that require the
development of new analysis techniques as
well as theoretical modeling. This will
necessitate close contact between
inflationary model builders,
phenomenologists and observers. This
workshop aims at fostering and
strengthening these ties. In addition to
broadly accessible overviews of all
aspects of primordial non-Gaussianity, the
workshop will allow a significant amount
of time for informal discussions and the
development of new research
collaborations.
May 20 – June 10
A Window on the
Formation of the Milky Way
Organizers:
Pau Amaro-Seoane*,
Max-Planck Institute
Matthew Benacquista, University
of Texas at Brownsville
Roberto Capuzzo-Dolcetta,
University of Roma La Sapienza
Sofia Randich, INAF
Rainer Schoedel, Instituto
de Astrofisica de Andalucia
Dense stellar systems such as galactic
nuclei and stellar clusters are unique
laboratories to astrophysics. The high
stellar densities that are found in their
centers are at least a million times
higher than in the solar neighbourhood.
Therefore, the interaction among stars
plays a dominant role in the global
evolution of such systems. The complexity
these systems is such that, in spite of
the huge theoretical, observational and
numerical effort, there are still a large
number of open key questions. The precise
astrometric observations that we will be
able to make in the near future in our own
galaxy of stars and their motions contain
crucial information on the star formation
history, the origin, and the evolution of
the Milky Way, its nucleus and the
globular clusters. In order to develop a
single narrative of the formation of
galaxies such as the Milky Way and to
understand the intricate dynamics of dense
clusters, it is important for theorists,
observers, and people working on
astrophysical simulations to work together
to develop strategies to piece together
this picture.
May 27 – June 17
Physics of Behavior
Organizers:
Ila Fiete, University of
Texas, Austin
Ilya Nemenman, Emory
University
Leslie Osborne , University
of Chicago
William Ryu*, University of
Toronto
Greg Stephens,
Princeton University
The idea of the workshop
stems from the understanding that the role
of physics in biology is broad, as
physical constraints define the strategies
and the biological machinery that living
systems use to shape their behavior in the
dynamic, noisy, and resource-limited
physical world. To date, such holistic,
physics-driven picture of behavior has
been achieved, arguably, only for
bacterial chemotaxis. Can a similar
understanding emerge for other, more
complex living systems? To begin answering
this, the workshop will bring together a
diverse group of scientists, from field
biologists to theoretical physicists,
broadly interested in animal behavior. We
would like to broaden the horizons of
physicists by inviting experts who
quantify behavior of a wide range of model
organisms, from molecular circuits to
mammals. We would like to explore behavior
as possibly optimal responses given the
physical and the statistical structure of
environment. Our topics will include, in
particular, navigation and foraging, a
ctive sensing, locomotion and rhythmic
behavior, and learning, memory, and
adaptive behaviors.
June 10 – July 1
The Physics of
Feedback Processes and their Role in
Galaxy Evolution
Organizers:
Giuseppina Fabbiano*,
Harvard University
Philip Hopkins, University
of California, Berkeley
Vassiliki Kalogera,
Northwestern University
Chris Reynolds , University
of Maryland
Feedback processes in
galaxies are widely believed to have an
important role in galaxy evolution.
Feedback from nuclear super–massive black
holes (SMBHs) has been advocated as a
major ingredient in reconciling
cosmological simulations to the observed
properties of galaxies at different
redshift, by dampening/quenching active
star formation. Feedback from supernovae
is clearly important in the heating and
chemical enrichment of the ISM, producing
the X–ray signatures detected with Chandra
in mergers, starburst galaxies, and
elliptical galaxies. Most recently, it has
been discussed that even feedback from
active X–ray emitting binaries may have an
effect on the evolution of galaxies.
While the average energy
input of these processes can be estimated,
the detailed physical processes
responsible for the transfer of energy to
the host galaxies and their components
have not been satisfactorily addressed.
Energetically, SMBH accretion can easily
supply sufficient energy to unbind the ISM
of a galaxy, and so stop star formation.
Whether AGNs actually do quench star
formation however is unclear. Similarly,
current merging simulations do not easily
reproduce the observational evidence for
X–ray hot, structured and metal enriched
halos in mergers. Most simulations use
feedback as an input parameter, but have
not tried to model the physics of this
process. Recently, thanks to
high–resolution observations, from radio
to X–rays, the physics of feedback has
begun to receive more attention, and the
current situation is rapidly evolving with
exciting prospects for progress and
improved understanding.
This summer Aspen
workshop will be confronting the issues
involved and addressing futures
approaches, both theoretical and
observational, that will produce a better
understanding of the detailed physical
processes responsible for shaping the
evolution of galaxies. Topics will
include:
1) The need for feedback in galaxy
evolution – latest update from simulations
and observations
o Red, dead galaxies
o Maximum galaxy mass, cooling flows
o Is M–sigma linked to evolution?
o SFR, Mdot(SMBH) vs. z latest
“Madau–Lilly” plot
2) AGN feedback
o Jets: cluster, galaxy cavities;
“radio–mode”
o winds: electron–, line–, dust–driven;
bi–cones.
o radiation: Compton heating.
o Not just dumping energy: 2nd order
mechanisms
o Quiescent SMBHs
3) Stellar evolution and feedback:
o Core collapse supernovae in actively
star forming galaxies: implications for
physical and chemical evolutions
o Type Ia supernovae in elliptical
galaxies: physical and chemical evolution
of the halos; nuclear accretion; age and
spatial distribution of SNIa progenitors
o Bright, hard X–ray binaries (accreting
neutron stars and black holes) as
potential feedback sources; their
formation and evolution at high resdshifts
coupled to the star formation history of
the Universe
4) Future outlooks for theory,
observations, and instrumentation
June 10 - July 1
Stochastic Flows and
Climate Modeling
Organizers:
James Y–K. Cho, Queen
Mary University of London
John Bradley Marston*,
Brown University
Jin–Song von Storch, Max
Planck Institute for Meteorology
Paul Williams, University of
Reading, UK
Stochastic processes can
be used to model systems in which two or
more spatio-temporal scales interact.
Turbulent flows, weather, and climate are
prime examples. Typically, the small/fast
scale is treated as a random influence on
the large/slow scale. The workshop will
focus on improved understanding of
geophysical and astrophysical flows made
possible by stochastic modeling. In
particular, advances in computing power
and algorithms permit a direct comparison
of stochastic models to numerical
simulations. The power and limitations of
the stochastic approach need to be better
established, however. The tension between
simple and complex models will be explored
within the context of how stochastic
approaches can address the enormous range
of spatial and process scales inherent in
flow and climate systems. The workshop
will bring together climate scientists,
astrophysicists, applied mathematicians,
and physicists to stimulate
interdisciplinary research in these
directions.
June 17 - July 1
The Evolution of
Massive Stars and Progenitors of GRBs
Organizers:
Andrew Fruchter, Space
Telescope Science Institute
Norbert Langer,
University of Bonn
Emily Levesque,
University of Colorado
Philip Massey, Lowell
Observatory
Georges Meynet, Geneva
Observatory
< strong>Maryam Modjaz*, New York
University
Alicia Soderberg, Harvard
University
Long-duration gamma-ray bursts (LGRBs),
associated with the core-collapse deaths
of unusual massive stars, are the fleeting
signatures of extraordinarily high-energy
events occurring throughout our universe.
These phenomena hold enormous promise as
cosmological tools, but the full potential
of LGRBs cannot be realized without first
gaining a thorough understanding of their
massive stellar progenitors. Recent
advances in the massive star community on
binarity, mass loss, and the effects of
metallicity are all critical to current
debates surrounding the nature of LGRB
progenitors. Simultaneously, new results
in the LGRB community have yielded
important insights into the physical
properties, environmental dependences, and
interior structures of the most extreme
massive stars. However, the study of
massive stellar evolution and the study of
LGRBs have long been seen as separate
pursuits within astronomy, with only
limited communication between the two
subfields. This multi-disciplinary
workshop will bring together leaders in
these complementary disciplines, offering
an opportunity for participants to
exchange expertise, share recent results,
and consider the most pressing current
questions that will shape the future of
LGRB and massive star research for years
to come.
July 1 - July 22
Exact Results in
Gauge Theory and their Applications
Organizers:
Christopher Herzog,
Princeton University
Daniel Jafferis*, Harvard
University
Anton Kapustin, Caltech
Igor Klebanov, Princeton
University
New methods and exact
results have introduced a rich new
playground for formal development in our
understanding of gauge theories,
especially those with supersymmetry. This
workshop will emphasize localization
techniques, supersymmetric indices,
non-perturbative dualities, relations
between field theories in different
dimensions, measures of the number of
degrees of freedom, and related topics.
The aim of the workshop is to build on the
recent formal progress, explore its
consequences, and look for its connections
and applications to specific physical
models.
To give a sense of the
breadth and inter-related nature of these
developments, recall that localization
reduces the Euclidean path integral of
supersymmetric gauge theories to a matrix
model integral over a finite number of
degrees of freedom. Localized path
integrals of three dimensional gauge
theories on a three sphere exhibit
interesting symmetries that have been used
to support long-standing non-perturbative
duality conjectures and to find new such
dualities. These matrix models have also
been used to confirm certain detailed
predictions of the Anti-de
Sitter/Conformal Field Theory
correspondence. It has been argued in
certain supersymmetric field theories that
the scaling dimensions of composite
operators are determined by maximizing the
free energy F on the 3-sphere. Like the
Weyl anomaly coefficients in
even-dimensional conformal field theories,
F may provide a measure of the number of
degrees of freedom in three dimensions.
These measures are also connected with
properties of the quantum entanglement
entropy. A recent proof of the a-theorem
in 4-d field theory adds further focus to
research on understanding measures of
degrees of freedom and their evolution
under renormalization group flows.
July 1 – July 29
Spin-Orbit Physics in
Correlated Electron Systems
Organizers:
Leon Balents*, University
of California, Santa Barbara
Yong-Baek Kim ,
University of Toronto
Hidenori Takagi,
University of Tokyo
Recently the understanding and control of
spin-orbit coupling have become subjects
of intensive research across many
different disciplines in condensed matter
physics. In particular, spin-orbit
coupling in correlated electron materials
has been appreciated for its role in
creating a new class of electronic states
that allow crossed-responses of the
electrons to electric and magnetic fields.
Several new collective states of matter
have been proposed in this context,
including novel spin-orbital ordered
states, spin liquid, various topological
phases, multipolar ordered phases,
skyrmion crystals etc. Equally important
is the availability of increasing number
of new quantum materials with significant
spin-orbit coupling, including several new
5d transition metal oxides (iridates,
osmates etc), multiferroic materials, and
heterostructures of transition metal
systems. The spin- orbit coupling in these
systems, is a critical determining factor
in the nature of the electronic states and
may lead to the emergence of entirely new
class of quantum many-body states. The
workshop aims to bring active researchers
from several different, but related,
disciplines and come up with coherent
themes for the research of
spin-orbit-induced phenomena in correlated
electron systems.
July 22 – August
12
The LHC Shows the Way
Organizers:
Csaba Csaki, Cornell
University
Andrew Liam Fitzpatrick ,
Boston University
Konstantin Matchev*,
University of Florida
Tim M.P. Tait ,
University of California, Irvine
Particle physics is at a
defining moment. The Large Hadron Collider
(LHC), after decades of anticipation, is
finally collecting data in earnest,
running at 7 TeV collision energy. By next
summer, the experiments are expected to
have data samples on the order of 10,000
pb–1. Once this data is processed and
analyzed, we will truly begin to explore
the mechanism of electroweak
symmetry–breaking. In particular, the data
will be sufficient to find evidence for or
discover the Standard Model Higgs over
most of the preferred mass range, and/or
explore many alternative models of
electroweak symmetry–breaking. This is a
unique opportunity for an Aspen workshop
to contribute to “rewriting the book”
of fundamental particles based on the
results of the LHC. The purpose of this
workshop is to bring together experts in
diverse areas including experimentalists,
phenomenologists, and model builders, in
order to synthesize the results of the LHC
data into a coherent picture.
July 29 – August
19
Large Fluctuations
and Collective Behavior in
Solids
Organizers:
Karin Dahmen , University
of Illinois, Urbana Champaign
Craig Maloney*, Carnegie
Mellon University
M. Carmen Miguel,
University of Barcelona
Damien Vandembroucq, ESPCI
This workshop will bring
together a mix of workers from across
theory, experiment, and numerical
modeling, working on a broad range of
systems which exhibit large fluctuations
and collective behavior in their
mechanical response. It will promote
interactions between participants from
condensed matter / statistical physics and
researchers at the boundary of physics and
other disciplines such as materials
science and solid mechanics. The workshop
will be organized around three primary
physical phenomena: 1) yielding in glassy
materials, 2) dislocation dynamics and 3)
fracture and fragmentation. The primary
aim of the workshop will be to catalyze
interactions between researchers to port
common theoretical and analytical tools
across the problem domains, and to connect
theory with experiments.
August 12 –
September 9
New Particle Physics
at the LHC and Its Connection to Dark
Matter
Organizers:
Yang Bai , Stanford
University
Rouven Essig*, Stanford
University
Yuri Gershtein, Rutgers
University
Andrew C. Haas, Stanford
University / SLAC
Jessie Shelton, Yale
University
Kathryn Zurek, University
of Michigan
With several inverse
femtobarn of LHC data allowing a detailed
probe of electroweak symmetry breaking, a
Standard Model Higgs will have been
discovered or disproven, new physics will
be discovered or increasingly constrained,
and the status of the Standard Model will
be under intense investigation.
Simultaneously, dark matter direct and
indirect detection experiments will
provide an orthogonal probe of weak-scale
interactions. Assembling a consistent
description of the emerging picture of the
weak scale is the focus of this workshop.
Participation by experimentalists is
highly encouraged.
August 19 –
September 9
Evolutionary Dynamics
and Information Hierarchies in
Biological Systems
Organizers:
Gyan Bhanot, Rutgers
University
Lynn Caporale, Rutgers
University
Sebastian Doniach*,
Stanford University
Alexandre V. Morozov,
Rutgers University
Mateo Pellegrini,
University of California, Los Angeles
Advances in genome sequencing are allowing
us to understand biochemical mechanisms
underlying the generation of variation in
the genome. The ability to compare genome
sequences from bacteria and viruses to
humans is elucidating the variety of ways
in which selection acts on the genome.
Organisms use a variety of mechanisms at
various length and time scales to store,
interpret and use information. The
information itself is organized in a large
and complex hierarchy: from DNA sequences
to chromatin regulation to intra/extra
cellular signaling to tissue/organ
organization to the interactions between
organisms and species. The overall theme
of the workshop is to summarize our
current understanding of information
hierarchies and discuss their influence on
the mechanisms that allow organisms to
interact, adapt, survive, reproduce and
evolve. The workshop will bring together
theorists and experimentalists who work on
biological systems functioning at various
length and time scales (cells, viruses,
bacteria, eukaryotes etc.), to provide a
forum in which they can share information
about their expertise, with the aim of
starting a dialogue which will begin the
synthesis of evolutionary development at
all length and time scales in the
information hierarchy.
August 19 – September 9
Disorder, Algorithms
and Complexity
Organizers:
Susan N. Coppersmith*, University
of Wisconsin
Jon Machta , University
of Massachusetts
Alan Middleton , Syracuse
University
Christopher Moore, University
of New Mexico
Lenka Zdeborová , CNRS
and CEA, France
This workshop will bring
together researchers in physics, computer
science, and mathematics to study complex
and disordered systems. Systems in all
three research areas share common
features, such as complex free energy
landscapes resulting from frustration,
phase transitions, subtle correlations,
and jamming. In physics, these systems
include amorphous and ordered packings,
spin glasses and random field magnets,
glassy or amorphous systems with frozen-in
disorder, pinned fluid interfaces,
colloids, RNA folding, and dense packings
of hard particles. In computer science,
they include satisfiability, graph
coloring, error-correcting codes,
compressed sensing, and inference and
learning problems. New approaches to these
problems include belief propagation,
high-temperature duality,
permanent-determinant methods, and
max-flow/min-cut algorithms. These
algorithms can provide results on complex
disordered systems that are inaccessible
to both experiment and previous
theoretical approaches. Moreover, many of
these algorithms have interesting dynamics
in their own right; they are based on a
deep conceptual understanding of the
physical system, and help advance that
understanding.
