davidoff404
May10-04, 05:02 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>\n\n\nI\'m wondering if anyone wishes to give their thoughts on the following.\nIn classical GR the scalar curvature of a manifold can be changed such\nthat R -> R - L. Now, everyone knows that this is essentially an\nintroduction of a cosmological constant into the field equations of\ngeneral relativity.\n\nRegardless of one\'s attitude towards experimental evidence for the\nexistence of a cosmological constant, one has to acknowledge that it\'s a\nbit of a fudge; we\'re effectively introducing a free parameter into the\nfield equations for the purpose of making GR agree with observation. I\'d\nlike to know your ideas on placing a bound on the value of L. As far as\nI know, standard GR will not allow you to restrict the possible values\nof L, so is there any way in which one can derive a result like L <=\nL_max, i.e., can we place an upper bound on the possible values of L\npurely from theory?\n\nI\'ve got only a passing familiarity with string theory and LQG, so any\npointers you could give towards the way in which these theories may\naddress the cosmological constant would be a great help.\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>I'm wondering if anyone wishes to give their thoughts on the following.
In classical GR the scalar curvature of a manifold can be changed such
that R -> R - L. Now, everyone knows that this is essentially an
introduction of a cosmological constant into the field equations of
general relativity.
Regardless of one's attitude towards experimental evidence for the
existence of a cosmological constant, one has to acknowledge that it's a
bit of a fudge; we're effectively introducing a free parameter into the
field equations for the purpose of making GR agree with observation. I'd
like to know your ideas on placing a bound on the value of L. As far as
I know, standard GR will not allow you to restrict the possible values
of L, so is there any way in which one can derive a result like L <=L_{max}, i.e., can we place an upper bound on the possible values of L
purely from theory?
I've got only a passing familiarity with string theory and LQG, so any
pointers you could give towards the way in which these theories may
address the cosmological constant would be a great help.
In classical GR the scalar curvature of a manifold can be changed such
that R -> R - L. Now, everyone knows that this is essentially an
introduction of a cosmological constant into the field equations of
general relativity.
Regardless of one's attitude towards experimental evidence for the
existence of a cosmological constant, one has to acknowledge that it's a
bit of a fudge; we're effectively introducing a free parameter into the
field equations for the purpose of making GR agree with observation. I'd
like to know your ideas on placing a bound on the value of L. As far as
I know, standard GR will not allow you to restrict the possible values
of L, so is there any way in which one can derive a result like L <=L_{max}, i.e., can we place an upper bound on the possible values of L
purely from theory?
I've got only a passing familiarity with string theory and LQG, so any
pointers you could give towards the way in which these theories may
address the cosmological constant would be a great help.