Cosmologists at Perimeter Institute seek to help pin down the constituents and history of our universe, and the rules governing its origin and evolution. Many of the most interesting clues about physics beyond the standard model (e.g., dark matter, dark energy, the matter/antimatter asymmetry, and the spectrum of primordial density perturbations], come from cosmological observations, and cosmological observations are often the best way to test or constrain a proposed modification of the laws of nature, since such observations can probe length scales, time scales, and energy scales that are beyond the reach of terrestrial laboratories.
Format results

15 talksCollection Number C17053
Talk

PSI 2017/2018  Cosmology  Lecture 1
Kendrick Smith Perimeter Institute for Theoretical Physics

PSI 2017/2018  Cosmology  Lecture 2
Kendrick Smith Perimeter Institute for Theoretical Physics

PSI 2017/2018  Cosmology  Lecture 3
Kendrick Smith Perimeter Institute for Theoretical Physics

PSI 2017/2018  Cosmology  Lecture 4
Kendrick Smith Perimeter Institute for Theoretical Physics

PSI 2017/2018  Cosmology  Lecture 5
Kendrick Smith Perimeter Institute for Theoretical Physics

PSI 2017/2018  Cosmology  Lecture 6
Kendrick Smith Perimeter Institute for Theoretical Physics

PSI 2017/2018  Cosmology  Lecture 7
Kendrick Smith Perimeter Institute for Theoretical Physics

PSI 2017/2018  Cosmology  Lecture 8
Kendrick Smith Perimeter Institute for Theoretical Physics


General Relativity for Cosmology (PHYS786/AMATH875)  Achim Kempf
24 talksCollection Number C17021Talk

General Relativity for Cosmology  Lecture 1
Achim Kempf University of Waterloo

General Relativity for Cosmology  Lecture 2
Achim Kempf University of Waterloo

General Relativity for Cosmology  Lecture 3
Achim Kempf University of Waterloo

General Relativity for Cosmology  Lecture 4
Achim Kempf University of Waterloo

General Relativity for Cosmology  Lecture 5
Achim Kempf University of Waterloo

General Relativity for Cosmology  Lecture 6
Achim Kempf University of Waterloo


General Relativity for Cosmology  Lecture 8
Achim Kempf University of Waterloo


Bounce Scenarios in Cosmology
16 talksCollection Number C17024Talk

Welcome and Opening Remarks

Steffen Gielen University of Sheffield

Neil Turok University of Edinburgh


Bounce in Loop Quantum Cosmology and its Implications
Abhay Ashtekar Pennsylvania State University

Observable Consequences of a Bounce
UeLi Pen Perimeter Institute for Theoretical Physics

Challenges for Bouncing Cosmologies
Robert Brandenberger McGill University  Department of Physics

Emergent bouncing cosmology from quantum gravity condensates
Edward WilsonEwing University of New Brunswick

Discussion Session 2

Angelika Fertig TotalEnergies (France)

Steffen Gielen University of Sheffield

Elizabeth Gould Arthur B. McDonald Canadian Astroparticle Physics Research Institute


Unitary Cosmological Bounces
Claudia de Rham Unknown School  United Kingdom

Quantum cosmological instabilities  with and without boundaries
JeanLuc Lehners Max Planck Institute for Gravitational Physics  Albert Einstein Institute (AEI)  Theoretical Cosmology


PSI 2016/2017  Explorations in Cosmology (Smith)
14 talksCollection Number C17012Talk

PSI 2016/2017  Explorations in Cosmology  Lecture 1
Kendrick Smith Perimeter Institute for Theoretical Physics

PSI 2016/2017  Explorations in Cosmology  Lecture 2
Kendrick Smith Perimeter Institute for Theoretical Physics

PSI 2016/2017  Explorations in Cosmology  Lecture 3
Kendrick Smith Perimeter Institute for Theoretical Physics

PSI 2016/2017  Explorations in Cosmology  Lecture 4
Kendrick Smith Perimeter Institute for Theoretical Physics

PSI 2016/2017  Explorations in Cosmology  Lecture 5
Kendrick Smith Perimeter Institute for Theoretical Physics

PSI 2016/2017  Explorations in Cosmology  Lecture 6
Kendrick Smith Perimeter Institute for Theoretical Physics

PSI 2016/2017  Explorations in Cosmology  Lecture 7
Kendrick Smith Perimeter Institute for Theoretical Physics

PSI 2016/2017  Explorations in Cosmology  Lecture 8
Kendrick Smith Perimeter Institute for Theoretical Physics


PSI 2016/2017  Cosmology (Kubiznak)
15 talksCollection Number C17003Talk

PSI 2016/2017  Cosmology (Review)  Lecture 1
David Kubiznak Charles University

PSI 2016/2017  Cosmology (Review)  Lecture 2
David Kubiznak Charles University

PSI 2016/2017  Cosmology (Review)  Lecture 3
David Kubiznak Charles University

PSI 2016/2017  Cosmology (Review)  Lecture 4
David Kubiznak Charles University

PSI 2016/2017  Cosmology (Review)  Lecture 5
David Kubiznak Charles University

PSI 2016/2017  Cosmology (Review)  Lecture 6
David Kubiznak Charles University

PSI 2016/2017  Cosmology (Review)  Lecture 7
David Kubiznak Charles University

PSI 2016/2017  Cosmology (Review)  Lecture 8
David Kubiznak Charles University


Time in Cosmology
14 talksCollection Number C16016Talk

Welcome and Opening Remarks

Marina Cortes Institute for Astrophysics and Space Sciences

Lee Smolin Perimeter Institute for Theoretical Physics

Neil Turok University of Edinburgh


The origin of arrows and time I

David Albert Columbia University

Steve Weinstein University of Waterloo


The origin of arrows of time II

Sean Carroll California Institute of Technology (Caltech)  Division of Physics Mathematics & Astronomy

Marina Cortes Institute for Astrophysics and Space Sciences

Tim Koslowski Universidad Nacional Autónoma De Mexico (UNAM)


The origin of arrows of time II cont.

Sean Carroll California Institute of Technology (Caltech)  Division of Physics Mathematics & Astronomy

Marina Cortes Institute for Astrophysics and Space Sciences

Tim Koslowski Universidad Nacional Autónoma De Mexico (UNAM)


Testing time asymmetry in the early universe

Brian Keating University of California, San Diego

Andrew Liddle University of Lisbon

Richard Muller University of California System


The fate of the big bang

Abhay Ashtekar Pennsylvania State University

Neil Turok University of Edinburgh


Time as Organization – Downward Caustation, Structure and Complexity I
Barbara Drossel Technische Universität Darmstadt

Time as Organization – Downward Caustation, Structure and Complexity II

Stuart Kauffman Santa Fe Institute (SFI)

George Ellis University of Cape Town



Cosmological Frontiers in Fundamental Physics 2016
21 talksCollection Number C16009Talk


Dark matter phenomenology across cosmic times
Yacine AliHaimoud Johns Hopkins University


The Classicality Puzzle
JeanLuc Lehners Max Planck Institute for Gravitational Physics  Albert Einstein Institute (AEI)  Theoretical Cosmology

Inhomogeneous Anisotropic Cosmology
Leonardo Senatore SLAC National Accelerator Laboratory

A new probe of primordial magnetic fields at high redshift
Vera Gluscevic University of Southern California

Turbulent gravity in asymptotically AdS spacetimes
Stephen Green Max Planck Institute for Gravitational Physics  Albert Einstein Institute (AEI)

Black hole ringdown and quasinormal modes
Aaron Zimmerman The University of Texas at Austin


Feedback over 44 Orders of Magnitude: From Gammarays to the Universe
22 talksCollection Number C16004Talk

30000 foot view of blazar heating
Christoph Pfrommer Universität Heidelberg  Institut für Theoretische Physik

The basics and notsobasic physics of beam plasmas
Antoine Bret University of CastillaLa Mancha

The Basics of the Gammaray Sky: current observational status and future perspectives
Jim Hinton Max Planck Institute for Gravitational Physics  Albert Einstein Institute (AEI)

The thermal state of the intergalactic medium and its effect on galaxy formation
Matthew McQuinn University of Washington

Models of Galaxy formation: Current constraints on the star formation history and feedback
Hojun Mo University of Massachusetts Amherst

Nonlinear Plasma Instabilities
Philip Chang University of WisconsinMilwaukee




PICITA Day 2015
Collection Number C15090 
Superluminality in Effective Field Theories for Cosmology
17 talksCollection Number C15019Talk


Causal structures in Massive gravity and GaussBonnet gravity
Keisuke Izumi National Taiwan University





Causality constraints and the lightcone
Timothy Hollowood Swansea University




Probing exotic energy injection with the CMB and early star formation
Wenzer Qin Massachusetts Institute of Technology (MIT)

PSI 2017/2018  Cosmology (Smith)
15 talksCollection Number C17053PSI 2017/2018  Cosmology (Smith) 
General Relativity for Cosmology (PHYS786/AMATH875)  Achim Kempf
24 talksCollection Number C17021General Relativity for Cosmology (PHYS786/AMATH875)  Achim Kempf 

PSI 2016/2017  Explorations in Cosmology (Smith)
14 talksCollection Number C17012PSI 2016/2017  Explorations in Cosmology (Smith) 
PSI 2016/2017  Cosmology (Kubiznak)
15 talksCollection Number C17003PSI 2016/2017  Cosmology (Kubiznak) 

Cosmological Frontiers in Fundamental Physics 2016
21 talksCollection Number C16009Cosmological Frontiers in Fundamental Physics 2016 
Feedback over 44 Orders of Magnitude: From Gammarays to the Universe
22 talksCollection Number C16004Feedback over 44 Orders of Magnitude: From Gammarays to the Universe


Superluminality in Effective Field Theories for Cosmology
17 talksCollection Number C15019Superluminality in Effective Field Theories for Cosmology 
Constraining a constant and tomographic Coupled Dark Energy model with low and high redshift probes
Lisa Goh CEA Saclay
The current ΛCDM concordance model has been widely successful in describing our Universe. However, crucial questions, such as the H0 tension, remain unanswered and are becoming increasingly critical with the continuous release of highprecision cosmological data. This has led to the exploration of modified ΛCDM models, one of them being the coupled quintessence, or Coupled Dark Energy (CDE) model. Here, we perform for the first time a tomographic analysis of coupled dark energy, where the coupling strength is parametrised and constrained in different redshift bins. We employ cosmic microwave background data from Planck, ACT and SPT, showing the impact of different choices that can be made in combining these datasets. Then, we use a range of low redshift probes to test CDE cosmologies, both for a constant and a tomographic coupling. In particular, we use for the first time data from weak lensing, galaxy clustering, and 3x2pt galaxygalaxy lensing crosscorrelation data. For CMB and background datasets, a tomographic coupling allows for β values up to one order of magnitude larger than in previous works, in particular at z < 1. The use of 3x2pt analysis then becomes important to constrain β at low redshifts, even when coupling is allowed to vary: for 3x2pt we find, at 0.5 < z < 1, β = 0.018+0.007 −0.011, comparable to what CMB and background datasets would give for a constant coupling. This makes upcoming galaxy surveys potentially powerful probes to test CDE models at low redshifts.

Zoom link https://pitp.zoom.us/j/94442666279?pwd=OTgrMTZ5dTRzZmc2WFhuMkF3ekJzdz09

Probing exotic energy injection with the CMB and early star formation
Wenzer Qin Massachusetts Institute of Technology (MIT)
Dark matter interactions with Standard Model particles can inject energy at early times, altering the standard evolution of the early universe. In particular, this energy injection can perturb the spectrum of the cosmic microwave background (CMB) away from that of a perfect blackbody, alter the CMB anisotropy spectrum, and affect processes by which the first stars form. For this study, I will discuss recent work to upgrade the DarkHistory code package to more carefully track interactions among low energy electrons, hydrogen atoms, and radiation, in order to accurately compute the evolution of the CMB spectral distortion in the presence of Dark Matter energy injection. I will show results for the contribution to the spectral distortions from redshifts z < 3000 for arbitrary energy injection scenarios, new CMB anisotropy constraints on light dark matter, as well as the effect of exotic energy injection on early star formation.

Zoom link https://pitp.zoom.us/j/99559611185?pwd=bDFVdmpyVE5CbXVXVHdEL29Md0FXUT09