Introduction To Loop Quantum Gravity

marcus

The Marcel Grossmann triennial conference is a major indicator of what fields of research are active and people are interestied in hearing about in the areas of theoretical/experimental General Rel., Cosmology, Field theory on curved spacetime, Astrophysics, and suchlike. The last two meetings MG11 and MG12 averaged about 800 participants each---a big international gathering. This years's MG13 has 1021 registered participants.
http://ntsrvg9-5.icra.it/mg13/FMPro?...en.0=19&-find=
http://www.icra.it/mg/mg13/parallel_sessions.htm

So it's interesting that Loop is making a strong showing in the MG13 parallel sessions.
Many more talks, for example, than other QG approaches and than are String-related.
Also I was interested to see several Loop people are giving talks at more than one session. Rovelli (2)
Bianchi (2) Pawlowski (2) Vidotto (2)...

QG is broadly represented in the Plenary Sessions.
Martin Reuter is giving a plenary talk:
http://ntsrvg9-5.icra.it/mg13/FMPro?...0=19&-findall=
And Jan Ambjorn as well:
http://www.icra.it/mg/mg13/invited_s...ls.htm#ambjorn
To check for more look for links in the right hand column beside participants' names:
http://ntsrvg9-5.icra.it/mg13/FMPro?...en.0=19&-find=

Tony Padilla's giving a talk, don't want to lose the link:
http://ntsrvg9-5.icra.it/mg13/FMPro?...d=41805&-find=

marcus

In a little over a week there will be a QG summer school in Beijing---giving an introduction to Loop Quantum Gravity and related topics (Loop Cosmology, Spinfoam, Limits, LQG black hole, GroupFieldTheory, and Regge calculus). The speaker lineup can provide perspective on the current makeup of the field:
The 2nd BNU International Summer School on Quantum Gravity (Schedule)

13 Aug (Mon.) Coordinators: Yongge Ma, Sijie Gao
9:00-9:50 Jerzy Lewandowski: Canonical loop quantum gravity (1)
10:00-10:50 Jerzy Lewandowski: Canonical loop quantum gravity (2)
11:10-12:00 Benjamin Bahr: Introduction to Regge calculus (1)
2:30-3:20 Benjamin Bahr: Introduction to Regge calculus (2)
3:40-4:30 Jonathan Engle: Isolated horizon and BH entropy in loop quantum gravity (1)
4:40-5:30 Jonathan Engle: Isolated horizon and BH entropy in loop quantum gravity (2)

14 Aug (Tue.) Coordinators: Jinsong Yang, Bin Zhou
9:00-9:50 Jerzy Lewandowski: Canonical loop quantum gravity (3)
10:00-10:50 Jerzy Lewandowski: Canonical loop quantum gravity (4)
11:10-12:00 Benjamin Bahr: Introduction to Regge calculus (3)
2:30-3:20 Thomas Krajewski: Introduction to group field theory (1)
3:40-4:30 Jonathan Engle: Isolated horizon and BH entropy in loop quantum gravity (3)
4:40-5:30 Jonathan Engle: Isolated horizon and BH entropy in loop quantum gravity (4)

15 Aug (Wed.) Coordinator: Kinjal Banerjee
9:00-9:50 Jerzy Lewandowski: Canonical loop quantum gravity (5)
10:10-11:00 Abhay Ashtekar: Loop quantum cosmology (1)
11:15-12:05 Free Discussion (Chair: Jerzy Lewandowsk):
Loop quantum gravity, BH entropy, Regge calculus,…

16 Aug (Thu.) Coordinators: You Ding, Hong Lu
9:00-9:50 Etera Livine: Spinfoam representation of loop quantum gravity (1)
10:00-10:50 Etera Livine: Spinfoam representation of loop quantum gravity (2)
11:10-12:00 Abhay Ashtekar: Loop quantum cosmology (2)
2:30-3:20 John Barrett: Asymptotics of spin foam models (1)
3:40-4:30 Thomas Krajewski: Introduction to group field theory (2)
4:40-5:30 Thomas Krajewski: Introduction to group field theory (3)

16 Aug Public Lecture: Jingwen Lecture Hall
7:30pm-9:00pm Abhay Ashtekar: Big Bang and the Quantum: Einstein and Beyond

17 Aug (Fri.) Coordinators: Li Qin, Jonathan Engle
9:00-9:50 Etera Livine: Spinfoam representation of loop quantum gravity (3)
10:00-10:50 Etera Livine: Spinfoam representation of loop quantum gravity (4)
11:10-12:00 Abhay Ashtekar: Loop quantum cosmology (3)
2:30-3:20 John Barrett: Asymptotics of spin foam models (2)
3:30-4:20 John Barrett: Asymptotics of spin foam models (3)
4:40-5:30 Free Discussion (Chair: John Barrett):
Spin foams, Group field theory, Loop quantum cosmology,…
6:30pm Banquet

18 Aug (Sat.) Coordinator: Jerzy Lewandowski
9:00-9:50 Etera Livine: Spinfoam representation of loop quantum gravity (5)
10:00-10:50 Abhay Ashtekar: Loop quantum cosmology (4)
11:05-11:55 Free Discussion: (Chair: Abhay Ashtekar)-------11:55-12:00 Closing Session

I see that Lewandowski is giving 5 hour lectures on Canonical LQG. Livine is giving 5 on Spinfoam LQG, Ashtekar is giving 4 on Loop Cosmology, Engle 4 on Loop BH, Barrett 3 on Spinfoam limits, Bahr 3 on Regge, Krajewski 3 on GFT.

marcus

Webpages for Loops 2013 are online, it's interesting to see who they have on board for the International Advisory Committee, and who the local organizers are:

http://www.perimeterinstitute.ca/en/...s_13/Loops_13/

International Advisory Committee

Giovanni Ameliano-Camelia, University of Rome
Abhay Ashtekar, Pennsylvania State University
Fernando Barbero, Instituto de Estructura de la Materia
John Barrett, University of Nottingham
James Bjorken, SLAC
Martin Bojowald, Pennsylvania State University
Robert Brandenberger, McGill University
Alejandro Corichi, Pennsylvania State University
Fay Dowker, Imperial College, London
Rodolfo Gambini, Instituto de Fisica Facultad de Ciendias
Steve Giddings, University of California, Santa Barbara
Viqar Husain, University of New Brunswick
Ted Jacobson, University of Maryland
Kirill Krasnov, University of Nottingham
Jerzy Lewandowski, University of Warsaw
Stefano Liberati, SISSA
Etera Livine, Ens de Lyon
Renate Loll, Universiteit Utrecht
Joao Magueijo, Imperial College, London
Alex Maloney, McGill University
Matilde Marcolli, California Institute of Technology
Guillermo Mena, Instituto de Estructura de la Materia
Djordje Minic, Virginia Tech
Daniele Oriti, Albert Einstein Institute
Roberto Percacci, SISSA
Alejandro Perez, Centre de Physique Theorique
Jorge Pullin, Lousiana State University
Martin Reuter, Johannes Gutenberg Universitat
Vincent Rivasseau, Laboratoire de Physique Théorique d'Orsay
Carlo Rovelli, Centre de Physique Theorique
Thomas Thiemann, Institut für Theoretische Physik III
William Unruh, University of British Columbia

This is a Loops conference, but somebody has applied ecumenical outreach to the International Advisory Committee. We all know who Matilda Marcolli and Roberto Percacci are. It is great they are on board. And Rivasseau! And James Bjorken! And Ted Jacobson!!!
Alex Maloney is a young string star who has coauthored with Witten and made faculty at McGill. Probably everybody knows of Steve Giddings and Robert Brandenberger, who've been prominent in String Theory and in string-related Cosmology.
Wow this is Unitarian Universalist Loops 2.0
Maybe it is how it always OUGHT to have been. Am I dreaming?

To make the mix visual, I colored general QG phenomenology green, competing theories orange (Spectral Geometry, AsymSafe, CDT, CausalSets) and string magenta---with blue reserved for some all-purpose great people.

marcus

Who are the young Perimeter people who are doing the Local Organizer work for Loops 13?
Of course Lee Smolin is the main Perimeter host for the conference. But who else besides him is Local Organizing?
http://www.perimeterinstitute.ca/en/...s_13/Loops_13/
http://www.perimeterinstitute.ca/Eve...al_Organizers/


Local Organizers

Joseph Ben Geloun, Perimeter Institute
Eugenio Bianchi, Perimeter Institute
Valentin Bonzom, Perimeter Institute
Bianca Dittrich, Perimeter Institute
Astrid Eichhorn, Perimeter Institute
Cecilia Flori, Perimeter Institute
Laurent Freidel, Perimeter Institute
Steffen Gielen, Perimeter Institute
Florian Girelli, Perimeter Institute
Philipp Hoehn, Perimeter Institute
Mercedes Martin-Benito, Perimeter Institute
Flavio, Mercati, Perimeter Institute
Lee Smolin, Perimeter Institute

marcus

I misspoke in the previous post. The main hosts for Loops 2013 are THREE people: Bianca Dittrich, Laurent Freidel, and Lee Smolin.
Plus there is quite a large crew of Perimeter folk doing the local organizing. The International Scientific Advisory committee has an interesting makeup. If you haven't examined it yet please to scroll back a couple of posts and take a look.
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The next big triennial conference for quantum relativists will be "GR20" in Warsaw July 2013.
It actually comes a few weeks before Loops 2013. The announcement and conference webpages were just posted last week. I'll get the list of parallel sessions. This can help us get an idea of what the conference organizers think their research community is interested in, and where important developments are occurring.
http://gr20-amaldi10.edu.pl/index.php?id=18

Parallel sessions: Title (Chairpersons)
A1: Exact solutions and their interpretation (J. Bicak, J. Tafel)
A2: Mathematical relativity and other progress in classical gravity theory (P. Chrusciel)
A3: Modified gravity theories (P. Horava)
A4: Complex and conformal methods in classical and quantum gravity (M. Dunajski)
B1: Relativistic astrophysics (C. Miller, I. Mandel)
B2: Numerical relativity and astrophysical applications (N. Padmanabhan)
B3: Numerical relativity--methods, theoretical gravity and high energy applications (D. Garfinkle)
B4: Analytic approximations, perturbation theory, effective field theory methods and their applications (V. Cardoso, R. Porto)
B5: Observational cosmology (L. Verde)
B6: Theoretical/mathematical cosmology (R. Durrer)
C5: Experimental gravitation (J. Mueller, C. Laemmerzahl)
D1: Loop quantum gravity and spin foams (T. Pawlowski, B. Dittrich)
D2: Strings, branes and M-theory (R. Gopakumar)
D3: Causal sets, causal dynamical triangulations, non-commutative geometry,
and other approaches to quantum gravity (J. Jurkiewicz)
D4: Quantum fields in curved space-time, semiclassical gravity, quantum gravity phenomenology,
and analog models (C. Fewster, S. Liberati)

I'm struck by the fact that Dittrich and Pawlowski are chairing the LQG session. Dittrich has in progress what seems to me to be a bid to reformulate LQG spin foam dynamics in terms of holonomy spin foams offering the prospect of already well-developed coarse-graining techniques (among other expected benefits.) I think she now has a permanent or faculty position at Perimeter, possibly split with AEI-Potsdam, and a fair number of collaborators working with her on this project.
Tom Pawlowski has also been working in an interesting direction recently. Loop early universe cosmology and inflation. Andrea Dapor (one of his co-authors) gave two talks about this work recently at the triennial Marcel Grossmann meeting in Stockholm. Here for reference his most recent 4 papers:
1. arXiv:1207.4353
Inflation from non-minimally coupled scalar field in loop quantum cosmology
Michal Artymowski, Andrea Dapor, Tomasz Pawlowski
14 pages, 5 figures
2. arXiv:1112.0360
Positive cosmological constant in loop quantum cosmology
Tomasz Pawlowski, Abhay Ashtekar
36 pages, 6 figures
Phys. Rev. D 85, 064001 (2012)
3. arXiv:1108.1147
Dust reference frame in quantum cosmology
Viqar Husain, Tomasz Pawlowski
8 pages
4. arXiv:1108.1145
Time and a physical Hamiltonian for quantum gravity
Viqar Husain, Tomasz Pawlowski
5 pages, version to appear in Phys. Rev. Lett

I'm impressed that not only does GR20 provide a session for LQG/SF chaired by these two people but also there is a separate session devoted to: Causal sets, causal dynamical triangulations, non-commutative geometry, and other approaches to quantum gravity. The chairman Jurkiewicz has co-authored many CDT papers with Ambjorn and Loll.