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PERIMETER INSTITUTE RECORDED SEMINAR ARCHIVE

Displaying all lectures given by: Abhay Ashtekar


PIRSA:19110090  ( MP4 Medium Res , MP3 , PDF ) Which Format?
Implications of the Quantum Nature Space-time for the Big Bang and Black Holes
Speaker(s): Abhay Ashtekar
Abstract:
Date: 19/11/2019 - 9:30 am

PIRSA:17060095  ( MP4 Medium Res , MP3 , PDF ) Which Format?
Bounce in Loop Quantum Cosmology and its Implications
Speaker(s): Abhay Ashtekar
Abstract: There is a huge body of work in Loop Quantum Cosmology comprising of several thousand journal articles. I will provide an overview of conclusions, focusing on the difficult conceptual and mathematical issues that accompany the notion of a bounce and opening the way for phenomenological implications ... read more
Date: 26/06/2017 - 10:05 am

PIRSA:16080055  ( MP4 Medium Res , MP3 , PDF ) Which Format?
The BMS group, conservation laws and soft gravitons
Speaker(s): Abhay Ashtekar
Abstract:

I will give a broad overview of this old subject which has come back to light recently in connection with the issue of black hole evaporation. It will be an informal, black board talk.

Date: 11/08/2016 - 2:30 pm

PIRSA:16060112  ( MP4 Medium Res , MP3 , PDF ) Which Format?
The fate of the big bang
Abstract:
Date: 28/06/2016 - 2:00 pm
Collection: Time in Cosmology

PIRSA:15050135  ( MP4 Medium Res , MP3 , PDF ) Which Format?
Even a tiny positive cosmological constant casts a long shadow
Speaker(s): Abhay Ashtekar
Abstract:
Date: 01/05/2015 - 12:00 pm

PIRSA:15030075  ( MP4 Medium Res , MP3 , PDF ) Which Format?
Even a tiny cosmological constant casts a long shadow
Speaker(s): Abhay Ashtekar
Abstract: Surprisingly, several basic questions in classical and quantum gravity, which were resolved some 40-50 years ago for zero $Lambda$, still remain open in the $Lambda >0$ case. In particular, for $Lambda >0$, we still do not have a satisfactory notion of gravitational radiation or Bondi ... read more
Date: 19/03/2015 - 1:00 pm

PIRSA:15010090  ( MP4 Medium Res , MP3 , PDF ) Which Format?
Loop Quantum Cosmology & The Very Early Universe Interplay between theory and Observations
Speaker(s): Abhay Ashtekar
Abstract: Thanks to the spectacular observational advances since the 1990s, a `standard model' of the early universe has now emerged. However, since it is based on quantum field theory in curved space-times, it is not applicable in the Planck era. Using techniques from loop quantum gravity, the theory can be ... read more
Date: 18/03/2015 - 2:00 pm
Series: Colloquium

PIRSA:13070083  ( MP4 Medium Res , MP4 Low Res , MP3 , PDF ) Which Format?
Promising Paths: What Have We Learned So Far About Quantum Gravity?
Abstract: 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 th... read more
Date: 26/07/2013 - 11:45 am
Collection: Loops 13

PIRSA:08120016  ( MP4 Medium Res , MP3 , PDF ) Which Format?
Why there is no information loss
Speaker(s): Abhay Ashtekar
Abstract: Using 2-dimensional CGHS black holes, I will argue that information is not lost in the Hawking evaporation because the quantum space-time is significantly larger than the classical one. I will begin with a discussion of the conceptual underpinnings of problem and then introduce a general, non-pertur... read more
Date: 04/12/2008 - 11:00 am

PIRSA:08120001  ( MP4 Medium Res , MP3 , PDF ) Which Format?
Quantum Nature of the Big bang in Simple Models.
Speaker(s): Abhay Ashtekar
Abstract: According to general relativity, space-time ends at singularities and classical physics just stops. In particular, the big bang is regarded as The Beginning. However, general relativity is incomplete because it ignores quantum effects. Through simple models, I will illustrate how the quantum nature ... read more
Date: 03/12/2008 - 2:00 pm
Series: Colloquium
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