Talks

12469 - 12480 of 20120 Results

Effective Field Theory of Multi-Field Inflation a la Weinberg

Nima Khosravi Shahid Beheshti University

July 30, 2013

PIRSA:13070091

Astrophysics
Quantum Foundations - 2

David Schroeren University of Oxford

Paolo Bertozzini Thammasat University

Bruno Hartmann

July 26, 2013

PIRSA:13070088
Mixed Session

Valerio Astuti

Seth Major Hamilton College

Michael Reisenberger Universidad de la Republica Uruguay

Jacobo Diaz-Polo

July 26, 2013

PIRSA:13070090
Renormalization - 3

Tobias Henz Universität Heidelberg - Institut für Theoretische Physik

Kevin Falls University of Sussex

Mohamed Anber University of Toronto

July 26, 2013

PIRSA:13070089
Quantum Cosmology - 5

Hector Hernandez Universidad Autonoma de Chihuahua

Edison Montoya Universidad de Antioquia

Matthew Hogan

Francesca Vidotto Western University

July 26, 2013

PIRSA:13070087
Discrete Approaches and Mixed Session

Goffredo Chirco Max Planck Institute for Gravitational Physics - Albert Einstein Institute (AEI)

Eugene Kur University of California, Berkeley

Christopher Duston Florida State University

Johannes Thuerigen University of Münster

Bianca Dittrich Perimeter Institute for Theoretical Physics

July 26, 2013

PIRSA:13070085
Quantum Cosmology - 4

Daniel Martin de Blas Universidade Federal do Espírito Santo

Adriano Contillo Radboud Universiteit Nijmegen

Marcin Kisielowski University of Warsaw

Eduardo Martin-Martinez University of Waterloo

July 26, 2013

PIRSA:13060026
Quantum Foundations - 1

Lee Smolin Perimeter Institute for Theoretical Physics

Robert Spekkens Perimeter Institute for Theoretical Physics

Robert Oeckl Universidad Nacional Autónoma De Mexico (UNAM)

Jonathan Oppenheim University College London

Markus Müller Austrian Academy of Sciences

July 26, 2013

PIRSA:13070084
Canonical Quantum Gravity and Spin Foams

Antonia Zipfel

Mingyi Zhang Aix-Marseille University

Atousa Chaharsough Shirazi

Fabio Anza Università di Pisa

Aristide Baratin SAIT AI Lab Montreal

July 26, 2013

PIRSA:13070086
Promising Paths: What Have We Learned So Far About Quantum Gravity?

Abhay Ashtekar Pennsylvania State University

Carlo Rovelli Aix-Marseille University

July 26, 2013

PIRSA:13070083
Scenes From Polymer Quantization

Viqar Husain University of New Brunswick

July 26, 2013

PIRSA:13070082
Diffeomorphism Invariant Gauge Theories

Kirill Krasnov University of Nottingham

July 26, 2013

PIRSA:13070081

Effective Field Theory of Multi-Field Inflation a la Weinberg

Nima Khosravi Shahid Beheshti University

July 30, 2013

PIRSA:13070091

Astrophysics

We
employ the effective field theory approach for multi-field inflation which is a
generalization of Weinberg's work. In this method the first correction terms in
addition to standard terms in the Lagrangian have been considered. These terms
contain up to the fourth derivative of the fields including the scalar field
and the metric. The results show the possible shapes of the interaction terms
resulting eventually in non-Gaussianity in a general formalism. In addition
generally the speed of sound is different but almost unity. Since in this
method the adiabatic mode is not discriminated initially so we define the
adiabatic as well as entropy modes for a specific two-field model. It has been
shown that the non-Gaussianity of the adiabatic mode and the entropy mode are
correlated in shape and amplitude. It is shown that even for speed close to
unity large non-Gaussianities are possible in multi-field case. The amount of
the non-Gaussianity depends on the curvature of the classical path in the
phase-space in the Hubble unit such that it is large for the large curvature.
In addition it is emphasized that the time derivative of adiabatic and entropy
perturbations do not transform due to the shift symmetry as well as the
original perturbations. Though two specific combinations of them are invariant
under such a symmetry and these combinations should be employed to construct an
effective field theory of multi-field inflation.
Quantum Foundations - 2

David Schroeren University of Oxford

Paolo Bertozzini Thammasat University

Bruno Hartmann

July 26, 2013

PIRSA:13070088
Mixed Session

Valerio Astuti

Seth Major Hamilton College

Michael Reisenberger Universidad de la Republica Uruguay

Jacobo Diaz-Polo

July 26, 2013

PIRSA:13070090
Renormalization - 3

Tobias Henz Universität Heidelberg - Institut für Theoretische Physik

Kevin Falls University of Sussex

Mohamed Anber University of Toronto

July 26, 2013

PIRSA:13070089
Quantum Cosmology - 5

Hector Hernandez Universidad Autonoma de Chihuahua

Edison Montoya Universidad de Antioquia

Matthew Hogan

Francesca Vidotto Western University

July 26, 2013

PIRSA:13070087
Discrete Approaches and Mixed Session

Goffredo Chirco Max Planck Institute for Gravitational Physics - Albert Einstein Institute (AEI)

Eugene Kur University of California, Berkeley

Christopher Duston Florida State University

Johannes Thuerigen University of Münster

Bianca Dittrich Perimeter Institute for Theoretical Physics

July 26, 2013

PIRSA:13070085
Quantum Cosmology - 4

Daniel Martin de Blas Universidade Federal do Espírito Santo

Adriano Contillo Radboud Universiteit Nijmegen

Marcin Kisielowski University of Warsaw

Eduardo Martin-Martinez University of Waterloo

July 26, 2013

PIRSA:13060026
Quantum Foundations - 1

Lee Smolin Perimeter Institute for Theoretical Physics

Robert Spekkens Perimeter Institute for Theoretical Physics

Robert Oeckl Universidad Nacional Autónoma De Mexico (UNAM)

Jonathan Oppenheim University College London

Markus Müller Austrian Academy of Sciences

July 26, 2013

PIRSA:13070084
Canonical Quantum Gravity and Spin Foams

Antonia Zipfel

Mingyi Zhang Aix-Marseille University

Atousa Chaharsough Shirazi

Fabio Anza Università di Pisa

Aristide Baratin SAIT AI Lab Montreal

July 26, 2013

PIRSA:13070086
Promising Paths: What Have We Learned So Far About Quantum Gravity?

Abhay Ashtekar Pennsylvania State University

Carlo Rovelli Aix-Marseille University

July 26, 2013

PIRSA:13070083

In LQG we work in the spirit of Antonio Machado: "Traveler, there is no path; Paths are made by walking." I will present a bird's eye view of some of the paths that have emerged since Loops 11 and offer a few suggestions.

I try to make the point about what we know and what we do not yet know about the possibility of writing a quantum theory of gravity.
Scenes From Polymer Quantization

Viqar Husain University of New Brunswick

July 26, 2013

PIRSA:13070082

A regime of "polymer quantum field theory on curved spacetime" should emerge in a low energy approximation of quantum gravity based on LQG ideas. This era should be characterized by a polymer scale, and give modifications to the usual semiclassical approximation. I will describe work on gravitational collapse, cosmology, and statistical mechanics in this setting. Results include models of horizon evaporation, inflation and graceful exit without an inflaton potential, and an indication of dimensional reduction from 4 to 2.5 dimensions.
Diffeomorphism Invariant Gauge Theories

Kirill Krasnov University of Nottingham

July 26, 2013

PIRSA:13070081

I will describe a very large class of gauge theories that do not use any external structure such as e.g. a spacetime metric in their construction. When the gauge group is taken to be SL(2) these theories describe interacting gravitons, with GR being just a particular member of a whole family of gravity theories. Taking larger gauge groups one obtains gravity coupled to various matter systems. In particular, I will show how gravity together with Yang-Mills gauge fields arise from one and the same diffeomorphism invariant gauge theory Lagrangian. Finally, I will describe what is known about these theories quantum mechanically.

Title	Date	Collection	Type	Info
Effective Field Theory of Multi-Field Inflation a la Weinberg	2013‑07‑30	Cosmology and Gravitation	Scientific Series	View details
Quantum Foundations - 2	2013‑07‑26	Loops 13	Conference	View details
Mixed Session	2013‑07‑26	Loops 13	Conference	View details
Renormalization - 3	2013‑07‑26	Loops 13	Conference	View details
Quantum Cosmology - 5	2013‑07‑26	Loops 13	Conference	View details
Discrete Approaches and Mixed Session	2013‑07‑26	Loops 13	Conference	View details
Quantum Cosmology - 4	2013‑07‑26	Loops 13	Conference	View details
Quantum Foundations - 1	2013‑07‑26	Loops 13	Conference	View details
Canonical Quantum Gravity and Spin Foams	2013‑07‑26	Loops 13	Conference	View details
Promising Paths: What Have We Learned So Far About Quantum Gravity?	2013‑07‑26	Loops 13	Conference	View details
Scenes From Polymer Quantization	2013‑07‑26	Loops 13	Conference	View details
Diffeomorphism Invariant Gauge Theories	2013‑07‑26	Loops 13	Conference	View details

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Format results

Effective Field Theory of Multi-Field Inflation a la Weinberg

Quantum Foundations - 2

Mixed Session

Renormalization - 3

Quantum Cosmology - 5

Discrete Approaches and Mixed Session

Quantum Cosmology - 4

Quantum Foundations - 1

Canonical Quantum Gravity and Spin Foams

Promising Paths: What Have We Learned So Far About Quantum Gravity?

Scenes From Polymer Quantization

Diffeomorphism Invariant Gauge Theories

Effective Field Theory of Multi-Field Inflation a la Weinberg

Quantum Foundations - 2

Mixed Session

Renormalization - 3

Quantum Cosmology - 5

Discrete Approaches and Mixed Session

Quantum Cosmology - 4

Quantum Foundations - 1

Canonical Quantum Gravity and Spin Foams

Promising Paths: What Have We Learned So Far About Quantum Gravity?

Scenes From Polymer Quantization

Diffeomorphism Invariant Gauge Theories