Carnegie Mellon Faculty in the McWilliams Center
Guy Blelloch
Professor, Computer Science
Guy Blelloch works on parallel algorithms and programming languages. In the area of algorithms, he has worked on algorithms for a variety of problems including meshing, n-body codes, sorting, computational biology, graph problems, and compact data representations. In the area of programming languages, he has worked on developing new language structures for parallelism and techniques for efficiently executing parallel codes.
Personal web page:
http://www.cs.cmu.edu/~guyb/
Roy Briere
Professor, Physics
Roy Briere concentrates on precision measurements in weak flavor physics as a means for searching for new physics beyond the current Standard Model. This method is complementary to direct searches for new particles at energy frontier machines. The weak interactions of quarks are currently the only known source of matter-antimatter (CP) symmetry violation, but the preponderance of matter over antimatter in our universe tells us that there must be an additional source of CP violation that is as yet undiscovered. He is also investigating options for making use of his experiences with large high-energy physics datasets by joining one of the new telescopic survey projects.
Personal web page:
http://www.cmu.edu/physics/people/faculty/briere.html
Rupert Croft
Associate Professor, Physics
Rupert Croft’s main research interests are in computational cosmology, involving both simulations and the analysis of large surveys. He primarily focuses on the physics of the intergalactic medium, its use as a probe of cosmology and of galaxy and quasar formation. He is a member of the SDSS-III survey of galaxies and quasar absorption lines which aims to measure dark energy parameters using large scale baryonic oscillatory features as a standard ruler. Croft also works on the interaction between matter and radiation in the intergalactic medium, on the re-ionization of the Universe, and predictions for future 21cm radio observations of this high redshift cosmological frontier. He makes use of the McWilliams Center’s high performance computing facilities, including Warp, the 700 core cluster to perform cosmological hydrodynamic and radiative transfer simulations.
Personal web page:
http://www.cmu.edu/physics/people/faculty/croft.html
Tiziana Di Matteo
Associate Professor, Physics
Tiziana is a theorist with expertise in both high energy astrophysics and cosmology. Her recent interests focus on state-of-the-art cosmological simulations of galaxy formation including detailed modeling of the impact of black hold feedback on structure formation. She has consistently been awarded large allocations of time on the largest national computing facilities and also makes use of the computational facilities of the McWilliams Center for Cosmology.
Personal web page:
http://www.cmu.edu/physics/people/faculty/dimatteo.html
Christos Faloutsos
Professor, Computer Science
Christos Faloutsos works on data mining for large datasets. He has been using the idea of fractal dimension to characterize clouds of points in n-dimensional space, the 'hadoop'/mapReduce architecture to handle large datasets, and spectral methods to analyze large graphs.
Personal web page:
http://www.cs.cmu.edu/~christos/
Peter Freeman
Project Scientist, Statistics
Peter Freeman's main research interest is the application of advanced statistical methods to astronomical data. Some of his recent work includes using nonparametric methods to estimate the foreground in CMB observations; using non-linear data transformation techniques to estimate photometric redshifts; and advancing source detection techniques in anticipation of LSST.Personal web page:
http://www.stat.cmu.edu/~pfreeman
Christopher Genovese
Professor, Statistics
Christopher Genovese's research involves high-dimensional and nonparametric inferences with applications to complex scientific problems. A major focus of his research is developing statistical methods for problems in astrophysics and cosmology, including analysis of the Cosmic Microwave Background, inference for the dark energy equation of state, and source detection.
Personal web page:
http://www.stat.cmu.edu/~genovese
Garth Gibson
Professor, Computer Science
Garth Gibson's research centers on large data processing and storage systems such as the world's largest parallel and distributed file systems for supercomputing and internet services. He leads a team that is exploring alternative parallel analysis computing models for large clusters (such as MapReduce) and applying these tools to astrophysics datasets that are terabytes to petabytes in size, and billions of particles in complexity.
Personal web page:
http://www.cs.cmu.edu/~garth
Fred Gilman
Dean, Mellon College of Science
Professor, Physics
Fred Gilman’s research is in theoretical particle physics, particularly in understanding the nature of CP violation Additional sources of CP violation that go beyond those in the Standard Model are required to explain the dominance of matter over antimatter in the universe, as well as to account for the particles that make up the dark matter. Gilman is Director of the McWilliams Center for Cosmology. He is a member of LSST Dark Energy Science Collaboration. Gilman serves on the Board of the Large Synoptic Survey Telescope Corporation and is Chair of the AURA Management Council for the LSST (AMCL) the oversees the project to construct, commission, and operate the LSST.
Personal web page:
www.cmu.edu/people/physics/people/faculty/gilman.html
Shirley Ho
Assistant Professor, Physics
Shirley Ho is a cosmologist whose interest ranges from theory to observations, and whose research involves both simulations and analysis of large scale structure surveys such as the Sloan Digital Sky Survey III or of the cosmic microwave background data from Planck HFI and LFI. She primarily works on utilizing the large scale structure and cosmic microwave background to understand the beginning of the Universe, the dark components of the Universe such as Dark Energy and Dark Matter and its lighter but equally elusive contents such as neutrinos and the evolution of the Universe. Her recent interest focuses on the use of a standard ruler called Baryon Acoustic Oscillations via various large scale structure tracers, such as the 3D clustering tracer of large scale structure.
Personal web site:
http://www.cmu.edu/physics/people/faculty/ho.html
Richard Holman
Professor, Physics
Rich Holman's research focuses mainly on early universe physics. In particular, the quantum field theory involved in understanding the inflationary paradigm has been at the forefront of his research program. His current work deals with how to use possible observations of non-gaussianity in the CMB to constrain the quantum vacuum the inflaton field. He is also interested in other aspects of astroparticle physics, such as how notions such as the landscape of string theory might be tested via observations of large scale structure.
Personal web page:
http://www.cmu.edu/physics/people/faculty/holman.html
Leonard Kisslinger
Professor (emeritus), Physics
Leonard Kisslinger's astrophysics research is in the general area of astroparticle physics. Much of his research is on the electroweak and QCD phase transitions, which occurred when the temperature of the universe was about 100 Gev and 150 MeV, respectively. He has been investigating the magnetic fields which are produced for possible polarization correlations in the CMB radiation and as seeds for the galactic and extragalactic magnetic fields which have been observed. Recently, in collaboration with Professor Tina Kahniashvili, he has worked on the gravitational waves produced by these phase transitions. Also, in collaboration with experimentalists and theorists at LANL, he has been studying the detection of quark/gluon plasma in RHIC experiments and the very large velocities of pulsars that are produced in a supernova collapse.
Personal web page:
http://www.cmu.edu/physics/people/faculty/kisslinger.html
Rachel Mandelbaum
Assistant Professor, Physics
Rachel Mandelbaum's research interests are predominantly in the areas of observational cosmology and galaxy studies. This work includes the use of weak gravitational lensing and other analysis techniques, with projects that range from development of improved data analysis methods, to actual application of such methods to existing data. Currently, she is focusing on data from the SDSS (including the ongoing SDSS-III), and is working on upcoming surveys including Hyper-SuprimeCam (HSC) and LSST.
Personal web page:
http://www.andrew.cmu.edu/user/rmandelb/
Manfred Paulini
Associate Professor, Physics
As an experimental high energy physicist, Manfred Paulini studies questions connecting particle physics to issues relevant to cosmology. One such question is the predominance of matter over antimatter in the universe, which requires that there is a breaking of the (CP) symmetry between matter and anti-matter in particle physics. As a member of the CDF experiment at Fermilab, Paulini studies the violation of CP symmetry and matter-antimatter oscillations in Bs mesons. Another question concerns the nature of dark matter that makes up about one quarter of the content of the universe. Paulini will search for the production of dark matter particles with the CMS experiment at CERN and will be analyzing the CMS data looking for supersymmetric particles with decay chains that involve the neutralino, a candidate for dark matter.
Personal web page:
http://www.cmu.edu/physics/people/faculty/paulini.html
Jeffrey Peterson
Professor, Physics
Jeff Peterson's group carries out cosmological observations using the 21 cm emission line of neutral hydrogen. The group is involved in projects using existing telescopes to make three dimensional maps of 21 cm emission for redshifts around ten. These maps will be used to study the first stars and their interaction with surrounding gas. The team also designs and builds 21 cm telescopes. In particular, the group is working to build the Cylinder Radio Telescope in Morocco. This 10,000 square meter telescope will map most of the sky at redshifts near one in order to constrain models of Dark Energy.
Personal web page:
http://www.cmu.edu/physics/people/faculty/peterson.html
Ira Rothstein
Professor, Physics
Ira Rothstein works on diverse topics in quantum field theory and general relativity. He focuses on developing field theoretic tools for the purpose of increasing predictive power in complex non-linear field theories, such as QCD and gravity. In the past, he has been particularly interested in developing effective field theory techniques in order to search for new physics in the Yukawa sector of the standard model. Presently he has been concentrating on a recent formalism (NRGR) developed to study binary inspirals and using NRGR to calculate higher order post-Newtonian corrections to these systems for the purpose of building gravity wave templates for LIGO and LISA. As with the rest of the particle physics community, he is anxiously awaiting the results from the LHC. The advent of data collection will be a very exciting time, hopefully with the discovery of new physics that will explain the dark matter as well as the hierarchy problem. Until then, he plans to work on finding methods to search for new physics in the model independent ways. In particular, he is interested in understanding how to determine at early stages of LHC running if we have produced new particles but have not been able to extract them from the background.
Personal web page:
http://www.cmu.edu/physics/people/faculty/rothstein.html
James Russ
Professor, Physics
James Russ is a particle experimentalist whose work impacts the physics goals of the McWilliams Center through his involvement with the CMS experiment at the Large Hadron Collider and his work on neutrino astronomy as a probe of Active Galactic Nuclei (AGN) over different red-shift ranges. At CMS we have an opportunity to discover evidence of extra dimensions and indications of a brane-world, which would revolutionize cosmology. The neutrino astronomy project offers insight into nature's highest-energy particle sources and is one of the few ways to put experimental limits on models of AGN physics.
Personal web page:
http://www.cmu.edu/physics/people/faculty/russ.html
Chad Schafer
Assistant Professor, Statistics
Chad Schafer's work focuses on addressing interference problems in the physical sciences using novel, often computationally-intensive, statistical methods. Projects in astronomy and cosmology include the development of methods for constructing optimally precise confidence regions for cosmological parameters, for estimating bivariate luminosity functions, and for estimating properties of galaxies via low-dimensional representations of their emission spectra.
Personal web page:
http://www.stat.cmu.edu/~cschafer
Jeff Schneider
Associate Research Professor, Robotics Institute
Jeff Schneider is pursuing active learning for scientific discovery. An active learning algorithm not only learns models from data, but also selects which experiments to run in order to collect the training data. Recent work focused on algorithms that select cosmological parameters for CMBFast runs in order to find those consistent with the WMAP data (Bryan et al., ApJ, 2007). This work has been extended to selecting across multiple model/data types (e.g., CMB, supernovae, large scale structure) with varying computational costs (Bryan and Schneider, ICML, 2008). Other current efforts include approaching anomaly detection as an active learning problem and learning dynamic models from static data.
Personal web page:
http://www.cs.cmu.edu/~schneide
Hy Trac
Assistant Professor, Physics
Hy Trac is a theoretical and computational cosmologist whose scientific interests include cosmic evolution and structure formation. He is actively working on understanding how the first generation of stars and galaxies re-ionize the universe and how the intergalactic medium can be studied using the Lyman alpha forest. As a member of the Atacama Cosmology Telescope (ACT) project, he is studying how galaxy clusters can be discovered through the Sunyaev-Zel'dovich effect. His research also focuses on the development and application of N-body, hydrodynamic, and radiative transfer algorithms.
Adrien Treuille
Assistant Professor, Computer Science
Adriene Treuille's research attempts to advance our understanding of very high-dimensional nonlinear phenomena. One thread of his research addresses the complexity of such systems by developing model reduction tools that generate compact representations. A complimentary thread seeks to control such systems. The mathematical techniques that he has developed have been applied to phenomena as diverse as animal morphology, human motion, and large fluid systems.
Personal web page:
http://www.cs.cmu.edu/~treuille/
Helmut Vogel
Professor, Physics
Helmut Vogel's main research interests are in high-energy particle physics experiments. For many years, he worked at LEP, the electron-positron colliding-beam accelerator which was the precursor to the LHC at CERN. Among its landmark results were a determination of the number of neutrino families in the universe and the most stringent lower limit to date on the mass of the Higgs boson. Presently, Vogel is a member of the CMS experiment at the LHC where he plans to study muons produced in the proton-proton collisions as probes of both "conventional" and "exotic" physics processes.
Personal web page:
http://www.cmu.edu/physics/people/faculty/vogel.html
Larry Wasserman
Professor, Statistics and Machine Learning
Larry Wasserman's research interests include nonparametric interference, high-dimensional models, and the development of statistical methods for astrophysics problems such as: estimating the equation of state of dark energy; the analysis of the cosmic microwave background radiation; and filament finding.
Personal web page:
http://www.stat.cmu.edu/~larry
Postdoctoral Fellows
Nishant Agarwal
McWilliams Postdoctoral Fellow, Physics
Nishant Agarwal is a theoretical cosmologist who is interested in studying and developing models for the evolution of the Universe. His main areas of research are the past (inflation) and present (dark energy) acceleration of the Universe. He studies different models of inflation, such as scalar field models and brane inflation, in the light of current observations. In the area of dark energy, his research focuses on theories based on large-scale modifications to gravity, such as scalar-tensor gravity, braneworld scenarios, and massive gravity. He is also interested in the astrophysical consequences of pseudoscalar-photon mixing, particularly on the polarization of CMB radiation and optical radiation from distant quasars.
Nicholas Battaglia
McWilliams Postdoctoral Fellow, Physics
Nick Battaglia works on cosmology and large-scale structure, focusing on galaxy clusters, the largest gravitationally bound objects in the Universe. He is currently involved in characterizing and simulating in large cosmological boxes the detailed physical processes of the intra-cluster medium, such as energetic feedback from active galactic nuclei and non-thermal pressure support. These processes contribute significantly to the overall energy budget of clusters and must be included in the interpretation of the latest high resolution cosmic microwave background observations from the Planck satellite, the Atacama Cosmology Telescope, and the South Pole Telescope.
Dustin Lang
McWilliams Postdoctoral Fellow, Physics
Dustin Lang is a computer scientist by training, who is interested in principled statistical data analysis problems in large astronomical surveys. In particular, he works on designing algorithms for making pixel-level measurements of stars and galaxies in tera-pixel (and upcoming peta-pixel) imaging collections, and connecting these measurements to higher-level scientific analyses. Weak gravitational lensing, a key cosmological probe, is one of the most challenging measurements and motivates much of this work. He works on projects and data including the Sloan Digital Sky Survey, Hyper-Suprime Cam, the Large Synoptic Survey Telescope, the Canada-France-Hawaii Telescope, BigBOSS, and the Hubble Space Telescope.
Mariana Vargas-Magaña
Postdoctoral Fellow, Physics
Mariana Vargas-Magaña is an observational cosmologist who is interested in the large scale structure of the universe and the observational probes designed to understand dark energy. She is currently involved in the BOSS collaboration, with her research focus on baryonic acoustic oscillations using luminous galaxies and, more recently, using the Lyman-alpha forest as a tracer of the matter. She is currently working on developing an improved reconstruction algorithm to recover the BAO feature erased by the non-linear evolution of density.
Aravind Natarajan
Postdoctoral Fellow, Physics
Aravind Natarajan works on many aspects of cosmology and particle astrophysics. His primary area of research is the mystery of dark matter, where he works on understanding the nature of dark matter through observations of the cosmic microwave background, direct detection experiments, and accelerator searches. He also works on the reionization of the Universe and on radio observations of the 21cm background from the spin flip of neutral Hydrogen.
Personal web page:
http://aravindnatarajan.com/
KwangHo Park
Urania-Stott Postdoctoral Fellow
KwangHo Park is a theoretical astrophysicist whose research interest is the growth and evolution of the first black holes formed from Population III stars in the early universe. He applies sub-grid scale radiation-hydrodynamic simulations of radiation-regulated accretion onto black holes to cosmological simulations. The effect of high energy emission of radiation from the black holes on the large-scale environment is also one of the main questions that could be answered.
Personal web page:
http://www.andrew.cmu.edu/user/kwanghop
Melanie Simet
Postdoctoral Fellow, Physics
Melanie Simet works on weak gravitational lensing, especially its applications to cosmology and galaxy cluster studies. She uses cosmological surveys to investigate the large-scale structure of matter (with tools such as cosmic shear and galaxy clustering) and to statistically probe smaller features such as the mass and concentration of cluster-sized dark matter haloes. Her research also involves related technical issues such as the calibration of photometric redshifts for upcoming surveys and the contamination in cosmic shear and cluster lensing signals from physical associations between lenses and lensed objects.
Personal web page:
http://www.andrew.cmu.edu/user/msimet
Xiaoying Xu
McWilliams Postdoctoral Fellow, Physics
Xiaoying Xu is interested in interfacing different scientific disciplines with cosmology. In particular, she is currently investigating the potential application of machine learning techniques to facilitate various aspects of cosmological analysis. She also works on using observational probes such as large-scale structure to understand the properties and evolution of dark energy in the Universe. In the future, she would also like to learn more about measuring primordial non-Gaussianity.
Visiting Faculty
Tina Kahniashvili
Visiting Professor, Physics
Tina Kahniashvili's research interests are in theoretical cosmology and astrophysics. Her research topics include tests of fundamental symmetries using cosmic microwave background radiation, the gravitational wave signal arising from cosmological phase transitions, primordial magnetic fields and their signatures, the effects of massive neutrinos on large scale structure formation, and magneto-hydrodynamic turbulence in astrophysical plasmas.