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DrRocket
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<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'> The first use of "information" that I'm aware of was the Bell's Theorem experiments. Later, the term was used in Hawking radiation and the "teleportation" experiments. Right now, it's more of a phenomenon and speculative. Hence, the irony.A bit of background: DeSitter was a contemporary of Einstein and proposed a different, generalized mathematical model of spacetime, compared to Einstein's. DeSitter spacetime is consistent with expansion, without a cosmological constant. Anti-DeSitter spacetime (AdS) is more similar than different but replaces the repulsive force with an attraction. AdS is not considered an accurate representation. Conceptually, the holographic principle is still mathematical, not physical. Fascinating area of research in which I have revolutionary expectations, hopefully in my lifetime. <br />Posted by SHU</DIV></p><p>To be a bit more precise, De Sitter discovered a solution to the Einstein field equations with a positive cosmological constant for a universe with no matter that results in an expanding universe.</p><p>His contribution was therefore not an alternative to general relativity, but rather a solution to the equations of general relativity that exposed the potential for an expanding universe long before the observational work of Hubble that provided empirical evidence of the expanion.</p><p>I am less optimistic than you that the holographic principle will eventually bear fruit. But what will really count is not my "feeling" but real results or lack of them. It is interestin conjecture, but the AdS/CFT correspondence that is in back of it remains conjecture ten years after it was proposed. A proof would do much to change my mind. </p><p>I am frankly developing an uneasy feeling with regard to quite a bit of the more speculative attempts at quantum gravity. M theory is based on a 1995 talk and paper by Ed Witten that provided a plausibility argument for the 5 competing versions of string theory in vogue at the time to in actuality be equivalent and just different aspects of a single theory -- M Theory. But so far as I know, the "dictionary" providing a translation among those 5 string theories and a unifying M Theory has never been actually produced. Similarly Maldecena's 1997 conjecture of a correspondence between anti-deSitter space and conformal field theory remains a conjecture, though many papers have addressed the implications if the conjecture is true. It seems to me that a lot is hanging on the truth or falsehood of these conjectures. <br /></p> <div class="Discussion_UserSignature"> </div>