Towards self dual Loop Quantum Gravity Jibril Ben Achour

In summary, the conversation discusses a new paper on a possible research direction for Loop Quantum Gravity (LQG). The paper, titled "Towards self dual Loop Quantum Gravity" by Jibril Ben Achour, presents a new strategy to investigate the kinematical and physical predictions of self dual LQG. The paper also discusses the benefits of making LQG self-dual, including a better semiclassical limit for black hole entropy calculations. The thesis also explores the role of the Immirzi parameter and its potential to be sent to a purely imaginary value to recover the self-dual quantum theory.
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kodama
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interesting new paper on possible new research direction for LQG

http://arxiv.org/abs/1511.07332
Towards self dual Loop Quantum Gravity
Jibril Ben Achour
(Submitted on 23 Nov 2015)
In this PhD thesis, we introduced a new strategy to investigate the kinematical and physical predictions of self dual Loop Quantum Gravity (LQG) and by-passed the old problem of implementing quantum mechanically the so called reality conditions inherent to the self dual Ashtekar's phase space.
We first review the loop quantization of the spherically isolated horizon and the computation of its micro-canonical entropy. Then we present the so called gas of punctures model for the quantum horizon, discussing its results in the canonical and grand-canonical ensembles and its limits.
The fourth chapter is devoted to studying to what extend the loop quantization based on the self dual variables could cure those problems. We introduce a new strategy, based on an analytic continuation of the degeneracy from γ∈R to γ=±i. We review in details the construction of the procedure, and present the results. At the leading term, we recover exactly the Bekenstein-Hawking area law.
The fifth chapter is devoted to understanding more precisely the interplay between the status of the Immirzi parameter. In order to do this, we introduce from a new toy model describing 2+1 gravity which depends explicitly on the Immirzi parameter.
Finally, the sixth chapter is devoted to applying our procedure to the simplest Loop Quantum Cosmology model. By first constructing the LQC dynamics for any arbitrary spin j and then implementing our analytic continuation, we show that our procedure preserves the key features of the LQC models, i.e. we obtain a bouncing universe which admits the right semi classical limit after the bounce.
PhD Thesis - 254 pages

worth remembering since the paper is about self-dual LQG
 
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good idea there marcus. when LQG when y= i it is self-dual. what are the benefits of making LQG self-dual
 
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It seems to be related to the line of work which tries to make Immizi imaginary. Originally the thinking was the Immirzi should be set to match the Hawking formula? But I think some more recent thinking on LQG black holes has imaginary Immirzi.

Eg. slide 17 of http://www.ihes.fr/~vanhove/Slides/NOUI-IHES-novembre2013.pdf

From Ben Achour's thesis in the OP (p79):
"Going further in our interpretation, the Immirzi parameter could be regarded as a kind of regulator, allowing to Wick rotate the kinematical quantum theory. At the end of the quantization procedure, should be sent to the purely imaginary value, in order to recover to self dual quantum theory. This is the point of view adopted in this manuscript."
 
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atyy said:
It seems to be related to the line of work which tries to make Immizi imaginary. Originally the thinking was the Immirzi should be set to match the Hawking formula? But I think some more recent thinking on LQG black holes has imaginary Immirzi.

Eg. slide 17 of http://www.ihes.fr/~vanhove/Slides/NOUI-IHES-novembre2013.pdf

From Ben Achour's thesis in the OP (p79):
"Going further in our interpretation, the Immirzi parameter could be regarded as a kind of regulator, allowing to Wick rotate the kinematical quantum theory. At the end of the quantization procedure, should be sent to the purely imaginary value, in order to recover to self dual quantum theory. This is the point of view adopted in this manuscript."

i recall Steve Carlip had a paper on that as well. his thesis is y = i results in better semiclassical black hole entropy calculation.

worth noting that the original kodama wave function y = i
 
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1. What is self-dual Loop Quantum Gravity?

Self-dual Loop Quantum Gravity is a theoretical framework that aims to unify the theories of general relativity and quantum mechanics. It proposes that space and time are not continuous, but rather made up of tiny discrete units called loops. These loops interact with each other in a self-dual manner, meaning that they are both the cause and effect of their own interactions.

2. Who is Jibril Ben Achour and what is his contribution to this theory?

Jibril Ben Achour is a Tunisian physicist who has made significant contributions to the field of self-dual Loop Quantum Gravity. He has published several papers on the subject, including his work on the use of spin networks to describe the quantum states of space and time. His work has helped to advance our understanding of this theory and its potential applications.

3. How does self-dual Loop Quantum Gravity differ from other theories of quantum gravity?

Unlike other theories of quantum gravity, which typically focus on quantizing the gravitational field, self-dual Loop Quantum Gravity also takes into account the quantum nature of space and time. This allows for a more complete and unified description of the universe at both the macroscopic and microscopic levels.

4. What are the potential implications of self-dual Loop Quantum Gravity?

If proven to be a valid theory, self-dual Loop Quantum Gravity could revolutionize our understanding of the universe. It could help to resolve long-standing issues in physics, such as the incompatibility of general relativity and quantum mechanics, and provide a more complete understanding of the nature of space and time.

5. What are the current challenges and limitations of self-dual Loop Quantum Gravity?

Self-dual Loop Quantum Gravity is still a highly theoretical and mathematical framework, and there is currently no experimental evidence to support its predictions. Additionally, there are still many unanswered questions and challenges, such as the incorporation of matter and the development of a consistent mathematical formalism. Further research and development are needed to fully understand and validate this theory.

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