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Some Possible Ways to Observe Consequences of Loop Quantum Gravity

Aurelien Barrau Laboratoire de Physique Subatomique et de Cosmologie (LPSC Grenoble)

July 22, 2013

PIRSA:13070036
A Quantum Gravity Extension of the Infationary Scenario

Ivan Agullo Louisiana State University

July 22, 2013

PIRSA:13070035
Opening Remarks

Neil Turok University of Edinburgh

July 22, 2013

PIRSA:13070093
Cosmological Consistency Relations as Ward Identities

July 11, 2013

PIRSA:13070016
Strings in Compact Cosmological Spaces

Ben Craps Vrije Universiteit Brussel

July 11, 2013

PIRSA:13070019
How much information is there in large scale structure?

July 11, 2013

PIRSA:13070018
Probing small-scale structure with dusty galaxies in the CMB

Neal Dalal Perimeter Institute for Theoretical Physics

July 11, 2013

PIRSA:13070017
Gravitational waves and stalled satellites from massive galaxy mergers at z < 1

Sean McWilliams Princeton University

July 11, 2013

PIRSA:13070027
The Microwave Background on small scales: Cosmological parameters from three seasons of data of the Atacama Cosmology Telescope (ACT).

July 10, 2013

PIRSA:13070009
The Information Paradox and an an Infalling Observer in AdS/CFT

Suvrat Raju

July 10, 2013

PIRSA:13070013
Black hole evaporation and unitarity: a semi-classical resolution?

James Bardeen

July 10, 2013

PIRSA:13070011
Testing inflation with combined power- and bispectrum

July 10, 2013

PIRSA:13070012

Some Possible Ways to Observe Consequences of Loop Quantum Gravity

Aurelien Barrau Laboratoire de Physique Subatomique et de Cosmologie (LPSC Grenoble)

July 22, 2013

PIRSA:13070036

In this talk, I'll briefly review some possible observational consequences of loop quantum gravity. I will first address the issue of the closure of the algebra of constraints in holonomy-corrected effective loop quantum cosmology for tensor, vector, and scalar modes. I will underline some unexpected features like a possible change of signature. The associated primordial power spectrum and the basics of the related CMB analysis will be presented. The "asymptotic silence" hypothesis will be mentioned as a promising alternative. Then, I'll address the issue of the probability for inflation and the prediction of its duration from a new perspective. Finally, I'll present some prospect about the evaporation of black holes in LQG.
A Quantum Gravity Extension of the Infationary Scenario

Ivan Agullo Louisiana State University

July 22, 2013

PIRSA:13070035

Since the standard inflationary paradigm is based on quantum field theory on classical space-times, it excludes the Planck era. Using techniques from loop quantum gravity, the theory is extended to overcome this limitations. The new framework sharpens conceptual issues by distinguishing between the true and apparent trans-Planckian difficulties and provides sufficient conditions under which the true difficulties can be overcome within a quantum gravity theory, with interesting lessons for both theory and observations.
Opening Remarks

Neil Turok University of Edinburgh

July 22, 2013

PIRSA:13070093
Cosmological Consistency Relations as Ward Identities

July 11, 2013

PIRSA:13070016
Strings in Compact Cosmological Spaces

Ben Craps Vrije Universiteit Brussel

July 11, 2013

PIRSA:13070019

A formalism is proposed for perturbative string theory in spacetimes with totally compact space (and non-compact time).
How much information is there in large scale structure?

July 11, 2013

PIRSA:13070018

Large scale structure contains vastly more Fourier modes than the CMB, and is therefore a promising arena for studying the early universe. One obstacle to using these modes is the non-linearity of structure formation. The amount of weakly coupled information available is therefore very sensitive to scale at which non-linear effects become important and simulations become necessary. Using effective field theory techniques, I will present evidence that the perturbative description of dark matter is much better behaved than previously thought. I will discuss the implications for improving constraints on non-gaussian initial conditions.
Probing small-scale structure with dusty galaxies in the CMB

Neal Dalal Perimeter Institute for Theoretical Physics

July 11, 2013

PIRSA:13070017
Gravitational waves and stalled satellites from massive galaxy mergers at z < 1

Sean McWilliams Princeton University

July 11, 2013

PIRSA:13070027

Pulsar timing arrays (PTAs), which are currently operating around the world and achieving remarkable sensitivities in the ~1--‐100 nHz band, will observe supermassive black holes (SMBHs) at redshifts z < ~1. Until now, all estimates of the anticipated signal strength of these sources have relied primarily on simulations to predict the relevant merger rates. I will present results from a completely new approach, which combines observational data and a fully self--‐consistent numerical evolution of the galaxy mass function. This method, which we will argue is superior to past estimates in several key ways, predicts a merger rate for massive galaxies that is ~10 times larger than that implied by previous calculations. I will explain why previous methods applied to this problem may systematically underestimate this merger rate, and one way in which our method may overestimate the rate, so that our approach has complementary systematic uncertainties in the worst case, and is an overall improvement in the best case. Finally, I will show that the new rate implies a range of possible signal strengths that is already in mild tension with PTA observations, with our model predicting a detection at the 95% confidence level as early as 2016. This could make PTAs the first instruments to directly detect gravitational waves, and will provide unprecedented information about the dynamics of merging galaxies, and merging bulges and supermassive black holes within those galaxies.
The Microwave Background on small scales: Cosmological parameters from three seasons of data of the Atacama Cosmology Telescope (ACT).

July 10, 2013

PIRSA:13070009

The Atacama Cosmology Telescope (ACT) has mapped the microwave sky to
arcminute scales. We present constraints on parameters from the observations at 148 and 217 GHz respectively by ACT from three years
of observations. Efficient map-making and spectrum-estimation techniques allow us to probe the acoustic peaks deep into the damping tail, and allow for
confirmation of the concordance model, and tests for deviations from
the standard cosmological picture. We fit a model of primary
cosmological and secondary foreground parameters to the dataset,
including contributions from both the thermal and kinetic
Sunyaev-Zel'dovich effect, Poisson distributed and correlated infrared
sources, radio sources and a term modeling the correlation between the
thermal SZ effect and the Cosmic Infrared Background. We will describe
the multi-frequency likelihood for the ACT data, and present
constraints on a variety of cosmological parameters using this
complete dataset, and put these results in context with the recent results from the Planck satellite.
The Information Paradox and an an Infalling Observer in AdS/CFT

Suvrat Raju

July 10, 2013

PIRSA:13070013
Black hole evaporation and unitarity: a semi-classical resolution?

James Bardeen

July 10, 2013

PIRSA:13070011

I explore the possibility that semi-classical back-reaction, due to the partners of the Hawking radiation quanta accumulating over the time for the black hole to lose about one half of its mass (the Page time), might cause the trapped surfaces to disappear, permitting unitary evolution without any cloning of quantum information.
Testing inflation with combined power- and bispectrum

July 10, 2013

PIRSA:13070012

Title	Speaker(s)	Date	Talk Type	Info link
Some Possible Ways to Observe Consequences of Loop Quantum Gravity	Aurelien Barrau	2013-07-22	Conference	View details
A Quantum Gravity Extension of the Infationary Scenario	Ivan Agullo	2013-07-22	Conference	View details
Opening Remarks	Neil Turok	2013-07-22	Conference	View details
Cosmological Consistency Relations as Ward Identities		2013-07-11	Conference	View details
Strings in Compact Cosmological Spaces	Ben Craps	2013-07-11	Conference	View details
How much information is there in large scale structure?		2013-07-11	Conference	View details
Probing small-scale structure with dusty galaxies in the CMB	Neal Dalal	2013-07-11	Conference	View details
Gravitational waves and stalled satellites from massive galaxy mergers at z < 1	Sean McWilliams	2013-07-11	Conference	View details
The Microwave Background on small scales: Cosmological parameters from three seasons of data of the Atacama Cosmology Telescope (ACT).		2013-07-10	Conference	View details
The Information Paradox and an an Infalling Observer in AdS/CFT	Suvrat Raju	2013-07-10	Conference	View details
Black hole evaporation and unitarity: a semi-classical resolution?	James Bardeen	2013-07-10	Conference	View details
Testing inflation with combined power- and bispectrum		2013-07-10	Conference	View details

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