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Is there a reason why a given universe should include only a single dimension attributed to time? Why not two? Or ten? Is there any particular law that prevents this?
Cheers
echolocator
Cheers
echolocator
Originally posted by echolocator
Is there a reason why a given universe should include only a single dimension attributed to time? Why not two? Or ten? Is there any particular law that prevents this?
Cheers
echolocator
Demystifier said:With number of times different from 1, the field equations of motion would not be hyperbolic. Then the corresponding dynamics would be typically unstable. A similar argument excludes tachyons.
yanniru said:I recall that the original 26-d closed string theory had two time dimensions as well as tachyons and was considered undesirable for both reasons. Does anyone have a similar recollection?
However, in reading Lisa Randall's book "Warped Passages", the claim is made that 26-d theory has but one time dimension. Is she correct and/or are both possibilities?
Demystifier said:With number of times different from 1, the field equations of motion would not be hyperbolic. Then the corresponding dynamics would be typically unstable. A similar argument excludes tachyons.
It seems that arivero is contradicting coalquay404 who in answer to my question said that 26-d string theory has only had one time dimension.arivero said:Clifford Algebras are classified by signature (number of spatial - number of temporal dimensions). It serves to string theoretists (and to Conway) to explain that 26 Minkowski is really a 24 dim thing.
yanniru said:It seems that arivero is contradicting coalquay404 who in answer to my question said that 26-d string theory has only had one time dimension.
Consider acceleration. We use time square in the denominator. So it is quite evident that the idea of time having more than one dimension is not only acceptable, it is necessary to explain ordinary phenomena.
R