T duality and scale factor [Archive]

Rene Meyer

Aug5-04, 11:33 AM

<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resizable=yes,status=no ,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>kurious <alistair@goforit64.fsnet.co.uk> wrote in message news:<kurious.1adzzd-100000@physicsforums.com>...\n\n> Universes with large scale factors are supposed to be equivalent\n> to universes with small scale factors under T duality.This means that a\n> universe with a larger redshift ,for the same distance, as another\n> universe, should be physically the same as the other universe.For this\n> to be correct then dark energy cannot be anything exotic - it must\n> transform under Tsymmetry like anything else - it must be a scalar\n> field of some kind, some kind of radiation, or some kind of baryonic\n> matter?\n\nI don\'t know wether T duality has anything to do with universes and\nredshifts. But I know it has only to do with some compactified\ndimensions in Type IIA and II B string theories. It just states that a\nType IIA theory compactified in one dimension of a given radius can be\nrelated to a Type IIB theory compactified on a circle with radius\nproportional to one over the radius of the compact dimensions of the\nIIA theory. Related to means here that the theories are physically\nequivalent in the sense that the spectrum of states is the same, but\nsome quantum numbers are interchanged, i.e. the winding number and the\nKaluza-Klein-state number of the string. To be correct, this all works\nout like this only in the case of closed string theories. For a more\nthorough review, have a look at\n\nhttp://arxiv.org/abs/hep-th/0207142\n\nRene.\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form">  View this Usenet post in original ASCII form </a></div><P></jabberwocky>kurious <alistair@goforit64.fsnet.co.uk> wrote in message news:<kurious.1adzzd-100000@physicsforums.com>...

> Universes with large scale factors are supposed to be equivalent
> to universes with small scale factors under T duality.This means that a
> universe with a larger redshift ,for the same distance, as another
> universe, should be physically the same as the other universe.For this
> to be correct then dark energy cannot be anything exotic - it must
> transform under Tsymmetry like anything else - it must be a scalar
> field of some kind, some kind of radiation, or some kind of baryonic
> matter?

I don't know wether T duality has anything to do with universes and
redshifts. But I know it has only to do with some compactified
dimensions in Type IIA and II B string theories. It just states that a
Type IIA theory compactified in one dimension of a given radius can be
related to a Type IIB theory compactified on a circle with radius
proportional to one over the radius of the compact dimensions of the
IIA theory. Related to means here that the theories are physically
equivalent in the sense that the spectrum of states is the same, but
some quantum numbers are interchanged, i.e. the winding number and the
Kaluza-Klein-state number of the string. To be correct, this all works
out like this only in the case of closed string theories. For a more
thorough review, have a look at

http://arxiv.org/abs/http://www.arxiv.org/abs/hep-th/0207142

Rene.