Talks

10189 - 10200 of 16754 Results

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
Planck and beyond

Martin Bucher French National Centre for Scientific Research (CNRS)

July 10, 2013

PIRSA:13070014
21cm cosmology

Ue-Li Pen Canadian Institute for Theoretical Astrophysics (CITA)

July 10, 2013

PIRSA:13070010
A unifying approach to dark energy models

David Langlois Université Paris Cité

July 09, 2013

PIRSA:13070023
Resolution of Cosmic Singularities and Bounces

Neil Turok University of Edinburgh

July 09, 2013

PIRSA:13070008

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
Planck and beyond

Martin Bucher French National Centre for Scientific Research (CNRS)

July 10, 2013

PIRSA:13070014

After reviewing some of the highlights of the implications of the Planck results for cosmic inflation (presentation to be coordinated with Hiranya Peiris), I will discuss some recent developments
regarding future searches for B modes and other new science resulting from an ultra-precise
characterization of the microwave and far-infrared sky in polarization. I will outline ideas for
a recently proposed large-class European Space Agency mission called PRISM.
21cm cosmology

Ue-Li Pen Canadian Institute for Theoretical Astrophysics (CITA)

July 10, 2013

PIRSA:13070010

I will overview the progress of 21cm cosmology, with emphasis on intensity mapping. Current and future experiments have the potential for precision measurements of dark energy, neutrino mass, and gravitational waves.
A unifying approach to dark energy models

David Langlois Université Paris Cité

July 09, 2013

PIRSA:13070023

This talk will present an effective description of single field dark energy/modified gravity models, which encompasses most existing proposals. The starting point is a generic Lagrangian expressed in terms of the lapse and of the extrinsic and intrinsic curvature tensors of the uniform scalar field hypersurfaces. By expanding this Lagrangian up to quadratic order, one can describe the homogeneous background and the dynamics of linear perturbations. In particular, one can identify seven Lagrangian operators that lead to equations of motion containing at most second order derivatives, the time-dependent coefficients of three of these operators characterizing the background evolution. I will illustrate this approach with Horndeski's---or generalized Galileon---theories. Finally, I will discuss the link between this effective approach and observations.
Resolution of Cosmic Singularities and Bounces

Neil Turok University of Edinburgh

July 09, 2013

PIRSA:13070008

The AdS/CFT correspondence provides new insights and tools to answer previously inaccessible questions in quantum gravity. Among the most interesting is whether it is possible to describe a cosmological "bounce" in a mathematically complete and consistent way. In the talk, I'll discuss joint work with M. Smolkin, developing the dual description of the simplest possible 4d M-theory cosmology in the stringy regime, employing the full quantum dynamics of its dual CFT. I'll also present evidence that the description extends to the Einstein-gravity regime.

Title	Date	Collection	Type	Info
Strings in Compact Cosmological Spaces	2013‑07‑11	Cosmological Frontiers in Fundamental Physics 2013	Conference	View details
How much information is there in large scale structure?	2013‑07‑11	Cosmological Frontiers in Fundamental Physics 2013	Conference	View details
Probing small-scale structure with dusty galaxies in the CMB	2013‑07‑11	Cosmological Frontiers in Fundamental Physics 2013	Conference	View details
Gravitational waves and stalled satellites from massive galaxy mergers at z < 1	2013‑07‑11	Cosmological Frontiers in Fundamental Physics 2013	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	Cosmological Frontiers in Fundamental Physics 2013	Conference	View details
The Information Paradox and an an Infalling Observer in AdS/CFT	2013‑07‑10	Cosmological Frontiers in Fundamental Physics 2013	Conference	View details
Black hole evaporation and unitarity: a semi-classical resolution?	2013‑07‑10	Cosmological Frontiers in Fundamental Physics 2013	Conference	View details
Testing inflation with combined power- and bispectrum	2013‑07‑10	Cosmological Frontiers in Fundamental Physics 2013	Conference	View details
Planck and beyond	2013‑07‑10	Cosmological Frontiers in Fundamental Physics 2013	Conference	View details
21cm cosmology	2013‑07‑10	Cosmological Frontiers in Fundamental Physics 2013	Conference	View details
A unifying approach to dark energy models	2013‑07‑09	Cosmological Frontiers in Fundamental Physics 2013	Conference	View details
Resolution of Cosmic Singularities and Bounces	2013‑07‑09	Cosmological Frontiers in Fundamental Physics 2013	Conference	View details

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