Associate

	Niayesh Afshordi PhD Princeton (2004) University of Waterloo
	Phone:	(519) 569-7600 x6532
	Email:	nafshordi[at]perimeterinstitute.ca
	Personal Webpage:	http://www.perimeterinstitute.ca/personal/nafshordi/index.htm

I am an Astronomer, and a Physicist; in short I am an Astrophysicist. 

I am an Assistant Professor in the Astrophysics and Gravitation group at the Department of Physics and Astronomy, University of Waterloo. I am also an Associate Faculty in the Cosmology group at the Perimeter Institute for Theoretical Physic (PI).

I dabble in Astrophysics, Cosmology, and Physics of gravity.  I am obsessed with observational hints that could help address problems in fundamental physics. In particular, I have found anomalous signatures of dark energy and dark baryons in the cosmic microwave background radiation. With other collaborators, I have also developed a curious theory for an incompressible dark energy, named cuscuton (after the Latin name for the parasitic plant of dodder). I am currently trying my hand in solving the cosmological constant problem through a new theory of gravity that can surprisingly relate the formation of astrophysical black holes to today’s acceleration of cosmic expansion. In a related inquiry, I am also exploring the relation of cuscuton and quantum gravity.  

Research Interests

Positions Held

• 2007-2009 Perimeter Institute for Theoretical Physics Distinguished Research Fellow
• 2004 - 2007 Institute for Theory and Computation (ITC), Harvard College Observatory, Harvard University ITC Postdoctoral Fellow
• 2000 - 2004 Department of Astrophysical Sciences, Princeton University Graduate Student

Awards

• Discovery Accelerator Supplement, Natural Sciences and Engineering Research Council of Canada (NSERC), 2010 (8 awarded across Canada in Physics)

Recent Publications

• Niayesh Afshordi, Roya Mohayaee, Edmund Bertschinger, Hierarchy in the Phase Space and Dark Matter Astronomy, Phys.Rev. D81 (2010) 10130, arxiv: 0911.0414
• Niayesh Afshordi, Reviving Gravity's Aether in Einstein's Universe, Physics in Canada (2010) 66.2, arxiv: 1004.2901
• Niayesh Afshordi (Perimeter Institute), Cuscuton and low energy limit of Horava-Lifshitz gravity, Phys.Rev. D80 (2009) 081502, arxiv: 0907.5201
• Chanda Prescod-Weinstein (Perimeter Institute/U-Waterloo), Niayesh Afshordi (Perimeter Institute), Michael L. Balogh (U-Waterloo), Stellar Black Holes and the Origin of Cosmic Acceleration, Phys. Rev. D 80, 043513 (2009), arxiv: 0905.3551
• Niayesh Afshordi, Ghazal Geshnizjani, Justin Khoury (Perimeter Institute), Observational Evidence for Cosmological-Scale Extra Dimensions, JCAP 08 (2009) 030, arxiv: 0812.2244
• Niayesh Afshordi (Perimeter Institute), Roya Mohayaee (IAP), Edmund Bertschinger (MIT), Hierarchical Phase Space Structure of Dark Matter Haloes: Tidal debris, Caustics, and Dark Matter annihilation, Phys. Rev. D 79, 083526 (2009), arxiv: 0811.1582
• Marilena LoVerde, Niayesh Afshordi, Extended Limber Approximation, Phys.Rev.D78:123506,2008, arxiv: 0809.5112
• Niayesh Afshordi, Andrew J. Tolley (Perimeter Institute), Primordial non-gaussianity, statistics of collapsed objects, and the Integrated Sachs-Wolfe effect, Phys.Rev.D78:123507,2008, arxiv: 0806.1046
• Georg Robbers, Niayesh Afshordi, Michael Doran, Does Planck mass run on the cosmological horizon scale?, Phys.Rev.Lett.100:111101,2008, arxiv: 0708.3235
• Niayesh Afshordi (Perimeter/Harvard), Fundamental Plane of Sunyaev-Zeldovich clusters, Astrophys.J. 686 (2008) 201-205, arxiv: 0704.2416
• Niayesh Afshordi (ITC, Harvard), Daniel J.H. Chung (UW-Madison), Michael Doran (Heidelberg), Ghazal Geshnizjani (UW-Madison), Cuscuton Cosmology: Dark Energy meets Modified Gravity, Phys.Rev.D75:123509,2007, arxiv: astro-ph/0702002
• Niayesh Afshordi (ITC, Harvard), Yen-Ting Lin (Princeton/Catolica), Daisuke Nagai (CalTech), Alastair J. R. Sanderson (Birmingham), Missing Thermal Energy of the Intracluster Medium, Mon.Not.Roy.Astron.Soc.378:293-300,2007, arxiv: astro-ph/0612700
• Niayesh Afshordi (ITC, Harvard), How well can (renormalized) perturbation theory predict dark matter clustering properties?, Phys.Rev.D75:021302,2007, arxiv: astro-ph/0610336
• Niayesh Afshordi (ITC, Harvard), Daniel J.H. Chung, Ghazal Geshnizjani (UW-Madison), Cuscuton: A Causal Field Theory with an Infinite Speed of Sound, Phys.Rev.D75:083513,2007, arxiv: hep-th/0609150
• Niayesh Afshordi (Harvard College Observatory), Intracluster Medium through three years of WMAP, NewAstron.Rev.50:905-908,2006, arxiv: astro-ph/0608503
• Niayesh Afshordi, Matias Zaldarriaga (Harvard), Kazunori Kohri (Harvard/Osaka), On the stability of Dark Energy with Mass-Varying Neutrinos, Phys.Rev. D72 (2005) 065024, arxiv: astro-ph/0506663
• Ghazal Geshnizjani, Daniel J.H. Chung (UW-Madison), Niayesh Afshordi (Harvard), Do Large-Scale Inhomogeneities Explain Away Dark Energy?, Phys.Rev. D72 (2005) 023517, arxiv: astro-ph/0503553
• Christopher M. Hirata, Abraham Loeb, Niayesh Afshordi, CMB B-mode polarization from Thomson scattering in the local universe, Phys.Rev. D71 (2005) 063531, arxiv: astro-ph/0501167
• Niayesh Afshordi, Banibrata Mukhopadhyay, Ramesh Narayan (ITC/Harvard), Bypass to Turbulence in Hydrodynamic Accretion: Lagrangian Analysis of Energy Growth, Astrophys.J. 629 (2005) 373-382, arxiv: astro-ph/0412194
• Banibrata Mukhopadhyay, Niayesh Afshordi, Ramesh Narayan (Harvard), Bypass to Turbulence in Hydrodynamic Accretion Disks: An Eigenvalue Approach, Astrophys.J. 629 (2005) 383-396, arxiv: astro-ph/0412193
• Niayesh Afshordi (Harvard/Princeton), Yen-Ting Lin (Illinois), Alastair J.R. Sanderson (Illinois/Birmingham), WMAP constraints on the Intra-Cluster Medium, Astrophys.J. 629 (2005) 1-14, arxiv: astro-ph/0408560
• Ghazal Geshnizjani, Niayesh Afshordi, Coarse-Grained Back Reaction in Single Scalar Field Driven Inflation, JCAP 0501 (2005) 011, arxiv: gr-qc/0405117
• Niayesh Afshordi (Princeton University Observatory), Integrated Sachs-Wolfe effect in Cross-Correlation: The Observer's Manual, Phys.Rev. D70 (2004) 083536, arxiv: astro-ph/0401166
• Niayesh Afshordi, Yeong-Shang Loh, Michael A. Strauss (Princeton University Observatory), Cross-Correlation of the Cosmic Microwave Background with the 2MASS Galaxy Survey: Signatures of Dark Energy, Hot Gas, and Point Sources, Phys.Rev. D69 (2004) 083524, arxiv: astro-ph/0308260
• N. Afshordi, P. McDonald, D.N. Spergel, Primordial Black Holes as Dark Matter: The Power Spectrum and Evaporation of Early Structures, Astrophys.J. 594 (2003) L71-L74, arxiv: astro-ph/0302035
• Niayesh Afshordi, Anze Slosar, Yi Wang, A Theory of a Spot, arxiv: 1006.5021
• Bruce A. Bassett, Niayesh Afshordi, The Non-Gaussian Sting in Posteriors arising from Marginal Detections, arxiv: 1005.1664
• Niayesh Afshordi, Dark Energy, Black Hole Entropy, and the First Precision Measurement in Quantum Gravity, arxiv: 1003.4811
• Niayesh Afshordi (Perimeter Institute), Gravitational Aether and the thermodynamic solution to the cosmological constant problem, arxiv: 0807.2639
• Physical Evidence for Dark Energy, R. Scranton, A. J. Connolly (UPitt), R. C. Nichol (CMU), A. Stebbins (FNAL), I. Szapudi (Hawaii), D. J. Eisenstein (Steward), N. Afshordi (Princeton), T. Budavari (JHU), I. Csabai (Eotvos), J. A. Frieman (FNAL), J. E. Gunn (Princeton), D. Johnson (CfCP), Y. Loh, R. H. Lupton (Princeton), C. J. Miller (CMU), E. S. Sheldon (CfCP), R. S. Sheth (UPitt), A. S. Szalay (JHU), M. Tegmark, Y. Xu (UPenn), et al. (SDSS collaboration), arxiv: astro-ph/0307335

Seminars

• "Non-linear Structure Formation in Cosmology" Invited Lectures, Institute for Research in Fundamental Sciences (IPM), Tehran
• "First Precision Measurement in Quantum Gravity" High Energy Physics Seminar, Institute for Research in Fundamental Sciences (IPM), Tehran (Aug. 2010)
• "Hierarchy in the Phase Space and Dark Matter Astronomy" Astrophysics seminar, Queen's University, Kingston, ON
• "Stellar Black Holes and the Thermodynamic Origin of Cosmic Acceleration" Invited Colloquium, Institut dAstrophysique de Paris
• "Cuscuton and solving the cosmological constant problem" High Energy Physics seminar, Physics department, Vanderbilt University
• "Stellar Black Holes and the origin of cosmic acceleration" Cosmology seminar, KIPAC, Stanford University, (Sep. 2009)
• "Stellar Black Holes and the origin of cosmic acceleration" Theory Canada 5, Fredericton, NB
• "Hierarchy in the Phase Space and Dark Matter Astronomy" -CYGNUS 2009 workshop on directional dark matter detection, MIT, Cambridge, MA
• "The End of the Cosmological Constant Problem" -Understanding the Dark Sector: Dark Matter and Dark Energy, Aspen Winter workshop, Aspen, CO
• "Primordial non-Gaussianity in Cosmology" Cosmology Seminar, Physics department, Sharif University of Technology, Tehran, Iran
• "Missing thermal energy of the Universe" Invited Contribution, Open questions from clusters of galaxies, OMP, Toulouse, France
• "Physics beyond the Horizon" Physics Colloquium, University of Pennsylvania
• "Fundamental Physics with the Integrated Sachs-Wolfe effect" Aspen CMB Conference, Aspen, CO
• "Our Tumultuous Journey into the Dark Side" Invited Physics Colloquium, York University
• "Fundamental Plane of Sunyaev-Zel'dovich clusters" Astrophysics of near-term Cosmological Observations, CITA, University of Toronto
• PIRSA:10050059, Cosmological constant problem: rethinking quantum and gravity, 2010-05-22, Laws of Nature: Their Nature and Knowability
• PIRSA:09120053, Cosmology - Review (PHYS 621) - Lecture 5, 2009-12-04, Perimeter Scholars International
• PIRSA:09120052, Cosmology - Review (PHYS 621) - Lecture 4, 2009-12-03, Perimeter Scholars International
• PIRSA:09120051, Cosmology - Review (PHYS 621) - Lecture 3, 2009-12-02, Perimeter Scholars International
• PIRSA:09120050, Cosmology - Review (PHYS 621) - Lecture 2, 2009-12-01, Perimeter Scholars International
• PIRSA:09110144, Cosmology - Review (PHYS 621) - Lecture 1, 2009-11-30, Perimeter Scholars International
• PIRSA:09110058, Cuscuton and Horava-Lifshitz gravity, 2009-11-09, Gravity at a Lifshitz Point
• PIRSA:09070014, Black hole horizons and the origin of cosmic acceleration, 2009-07-07, Holographic Cosmology Workshop
• PIRSA:09050088, Gravitational aether as a solution to the CC problem and more!, 2009-05-27, New Prospects for Solving the Cosmological Constant Problem
• PIRSA:09030036, (Towards) the end of the cosmological constant problem!, 2009-03-19, Cosmology
• PIRSA:08100062, Observational Evidence for Massive Gravity, 2008-10-23, PI CITA Joint Cosmology Day
• PIRSA:C08018, Sep.-Dec., 2008, Astrophysics & Cosmology Through Problems, Graduate Course Lecture Series (with Mark Wyman)
• PIRSA:08060144, Gravitational Aether as a solution to the cosmological constant problem, 2008-06-03, PASCOS 08
• PIRSA:08030069, Primordial non-Gaussianity, statistics of collapsed objects, and the ISW effect, 2008-03-10, Origins and Observations of Primodial Non-Gaussianity
• PIRSA:08020040, Physics beyond the Horizon, 2008-02-20, Colloquium
• PIRSA:08010043, Physics Beyond the Horizon, 2008-01-25, Cosmology