Arcadian Functor

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Marni D. Sheppeard

Monday, July 09, 2007

GRG18 Day 1

After disposing of a Kauri pine's worth of paper from the conference pack, I enjoyed the champagne and food at the conference reception Sunday evening, overlooking the lights of the city. Francis Everitt confirmed that the frame dragging effect measured by Gravity Probe B does agree well with the General Relativistic predictions. Further analysis will probably be completed around December.

Monday kicked off with a welcome ceremony and then the first plenary talk, by S. Whitcomb on ground based gravitational wave detection. He covered the history of resonant bar detectors and modern interferometers, including LIGO, Geo600, Virgo, TAMA300 and the crygenic CLIO detector. I must confess that I did not realise how many of these experiments there are! In 2005 LIGO reached its target sensitivity. The measure of sensitivity is "binary neutron stars at distance x". For LIGO this is around 15 Mpc and for Virgo 3.6 Mpc. Future plans include upgrades for LIGO (called Advanced LIGO) yielding a 10 times improvement in sensitivity, with a target installation date of 2011. Virgo has 2 phases of advanced planning: the first a 2 times improvement ready for science runs in 2010 and then Advanced Virgo set for installation in 2011. The decision for the former phase is to be made later this year. The GEO experiment should remain operational whilst LIGO and Virgo undergo these plans, allowing for possible supernovae observations. Futuristic plans include a large scale cryogenic telescope in Japan (LCGT), for which the main mirror would be cooled to 10K and the baseline would be 3km; and also new acoustic wave detectors.

The second speaker was Laurent Freidel, who tried to cover as many aspects of LQG as possible in one hour. He began by stating that the key issue here is the question of background independence, and then introduced Hamiltonian quantization before defining spin networks and then discussing spin foam models and group field theory. The last part of the talk included some interesting comments on QFTs on non-commutative spacetimes, or rather the necessity of curving momentum space and using a non-commutative geometry to discuss position operators.

The week is jam packed with talks, so I'll neglect to summarise the excellent talk on Large Stellar Systems and evidence for intermediate mass black holes in globular clusters. All this was before lunch time on Monday! And now I need to grab some food before Penrose's twistor theory talk in the parallel sessions...and there may be some envious eyes looking at me hogging one of only 5 computers in the central lounge.

3 Comments:

Blogger Matti Pitkanen said...

Hi Kea,

you are receiving quite an information flow! Enjoy!


Concerning blackholes, p-adic mass calculations led to a detailed TGD based microscopic description of blackholes as gigantic hadron like objects: GRT description certainly fails since only a part of interior metric is imbeddable as 4-surface.


Hawking-Bekenstein entropy is replaced with p-adic entropy. The requirement that horizon radius equals to Compton length gives rise to Nottale formula for Planck constant in case of self gravitation.

Neutron star represents super-canonical blackhole (gigantic hadronic space-time sheet) with ordinary matter still present. The transition from neutron star to "super-canonical" blackhole is quite smooth involving blackhole evaporation leading to the annihilation of ordinary matter. Super-canonical matter is strictly dark since it has no electro-weak interactions.

Hadronic space-time sheets represent small super-canonical blackholes and RHIC events, re-incarnated Pomeron, and strange cosmic ray events like Centauro, find nice description in terms of separation of valence quark system (Pomeron) from the super-canonical hadronic space-time sheet (mini blackhole). These blackholes will be produced in LHC. For details see my blog .

July 09, 2007 6:23 PM  
Blogger L. Riofrio said...

Hoping you have a nice conference. Sudney is wonderful this time of year.

July 10, 2007 3:57 PM  
Anonymous kneemo said...

What did you think of Penrose's talk?

July 12, 2007 5:52 AM  

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