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an effective introduction to Causal Sets is this 2004 set of lecture slides by Dowker
www.dpf2003.org/xx/qg/dowker.pdf[/URL]
the title of the talk is
"Causal Sets as the Deep Structure of Spacetime"
the slides are written-out enough to understand on their own, without the talk. there is an essential reference to a paper by Sorkin et al
Ahmed, Dodelson, Green, Sorkin
[url]http://www.arxiv.org/abs/astro-ph/0209274[/url]
and indirectly to a 1993 Sorkin talk published in 1997
[url]http://www.arxiv.org/abs/gr-qc/9706002[/url]
from Dowker slides one gets the impression that Causets is not a quantum theory yet, it has some probabilities you can calculate but no hilbertspace and no complex amplitudes. seems conceptually nice (if you like discrete finite sets and relations defined on them) but so far not so good for calculating or for imitating General Relativity spacetime dynamics.
however it has a strong appeal for philosophers
Dowker intimates that Sorkin got an amazingly close estimate of the size of the cosmological constant (which if true might be an accident or might mean something) back in 1992 or 1993 just using Causal Sets reasoning.
Causets is still somewhat nebulous as a theory IMO, so this thing about predicting the size of the cosmological constant, even if just an order of magnitude guess, is iffy. Also it is based on a strange picture where Lambda oscillates and we just happen to be in a era when it is E-120.
but even discounting the claim of predicting Lambda, causets is a lively contender for the Nonperturbative Limelight.
www.dpf2003.org/xx/qg/dowker.pdf[/URL]
the title of the talk is
"Causal Sets as the Deep Structure of Spacetime"
the slides are written-out enough to understand on their own, without the talk. there is an essential reference to a paper by Sorkin et al
Ahmed, Dodelson, Green, Sorkin
[url]http://www.arxiv.org/abs/astro-ph/0209274[/url]
and indirectly to a 1993 Sorkin talk published in 1997
[url]http://www.arxiv.org/abs/gr-qc/9706002[/url]
from Dowker slides one gets the impression that Causets is not a quantum theory yet, it has some probabilities you can calculate but no hilbertspace and no complex amplitudes. seems conceptually nice (if you like discrete finite sets and relations defined on them) but so far not so good for calculating or for imitating General Relativity spacetime dynamics.
however it has a strong appeal for philosophers
Dowker intimates that Sorkin got an amazingly close estimate of the size of the cosmological constant (which if true might be an accident or might mean something) back in 1992 or 1993 just using Causal Sets reasoning.
Causets is still somewhat nebulous as a theory IMO, so this thing about predicting the size of the cosmological constant, even if just an order of magnitude guess, is iffy. Also it is based on a strange picture where Lambda oscillates and we just happen to be in a era when it is E-120.
but even discounting the claim of predicting Lambda, causets is a lively contender for the Nonperturbative Limelight.
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