is space made up of gravitons? [Archive]

Daniel

Apr24-04, 08:18 PM

<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>according to GR, gravity is the geometry of spacetime.\n\naccording to QM, all periodic processes must be quantized. The quanta\nof gravity is the graviton.\n\nIt would seem to me that therefore space must be made of "atoms" of\ngravitons.\nSince gravitons are massless spin-2 particles that travel at the speed\nof light, and closed strings according to SMT, then is it correct to\nsay spacetime according to SMT must be made of massless spin-2\nparticles of closed strings.\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>according to GR, gravity is the geometry of spacetime.

according to QM, all periodic processes must be quantized. The quanta
of gravity is the graviton.

It would seem to me that therefore space must be made of "atoms" of
gravitons.
Since gravitons are massless spin-2 particles that travel at the speed
of light, and closed strings according to SMT, then is it correct to
say spacetime according to SMT must be made of massless spin-2
particles of closed strings.

Jacques Fric

Apr27-04, 01:55 PM

<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"Daniel" <ensabah6@yahoo.com> a écrit dans le message de\nnews:ba566c17.0404241235.b1d5bc9@posting.googl e.com...\n> according to GR, gravity is the geometry of spacetime.\n>\n> according to QM, all periodic processes must be quantized. The quanta\n> of gravity is the graviton.\n+++\nThat\'s incorrect, the graviton should be ( if it exists, as we should\nexpect, in a new theory to be developped, ) the quantum of gravitational\nwaves, the counterpart of the photon as electromagnetic waves.\nGravitation counterpart in this context should be fermionic fields\nassociated to charged particles\nJacques\n+++\n>\n> It would seem to me that therefore space must be made of "atoms" of\n> gravitons.\n> Since gravitons are massless spin-2 particles that travel at the speed\n> of light, and closed strings according to SMT, then is it correct to\n> say spacetime according to SMT must be made of massless spin-2\n> particles of closed strings.\n>\n\n\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>"Daniel" <ensabah6@yahoo.com> a écrit dans le message de
news:ba566c17.0404241235.b1d5bc9@posting.google.co m...
> according to GR, gravity is the geometry of spacetime.
>
> according to QM, all periodic processes must be quantized. The quanta
> of gravity is the graviton.
+++
That's incorrect, the graviton should be ( if it exists, as we should
expect, in a new theory to be developped, ) the quantum of gravitational
waves, the counterpart of the photon as electromagnetic waves.
Gravitation counterpart in this context should be fermionic fields
associated to charged particles
Jacques
+++
>
> It would seem to me that therefore space must be made of "atoms" of
> gravitons.
> Since gravitons are massless spin-2 particles that travel at the speed
> of light, and closed strings according to SMT, then is it correct to
> say spacetime according to SMT must be made of massless spin-2
> particles of closed strings.
>

Ioan Oprea

Apr28-04, 02:25 PM

<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>ensabah6@yahoo.com (Daniel) wrote in message news:<ba566c17.0404241235.b1d5bc9@posting.google.c om>...\n> according to GR, gravity is the geometry of spacetime.\n>\n> according to QM, all periodic processes must be quantized. The quanta\n> of gravity is the graviton.\n>\n> It would seem to me that therefore space must be made of "atoms" of\n> gravitons.\n> Since gravitons are massless spin-2 particles that travel at the speed\n> of light, and closed strings according to SMT, then is it correct to\n> say spacetime according to SMT must be made of massless spin-2\n> particles of closed strings.\n\nThe graviton is a perturbative concept. They exist only with respect\nto a background spacetime (usually, the Minkowski spacetime) on which\nthey propagate.\nBut the theory of quantum gravity is supposed to be nonperturbative.\nSo spacetime is not made of gravitons.\nActually, according to loop quantum gravity & spin foam models,\nspacetime is given merely by a combinatorial structure. In other\napproaches spacetime is a net of causal relations (this is not\nnecessarily unrelated to the combinatorial structure I\'ve mentioned\nbefore).\n\ni.o.\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>ensabah6@yahoo.com (Daniel) wrote in message news:<ba566c17.0404241235.b1d5bc9@posting.google.com>...
> according to GR, gravity is the geometry of spacetime.
>
> according to QM, all periodic processes must be quantized. The quanta
> of gravity is the graviton.
>
> It would seem to me that therefore space must be made of "atoms" of
> gravitons.
> Since gravitons are massless spin-2 particles that travel at the speed
> of light, and closed strings according to SMT, then is it correct to
> say spacetime according to SMT must be made of massless spin-2
> particles of closed strings.

The graviton is a perturbative concept. They exist only with respect
to a background spacetime (usually, the Minkowski spacetime) on which
they propagate.
But the theory of quantum gravity is supposed to be nonperturbative.
So spacetime is not made of gravitons.
Actually, according to loop quantum gravity & spin foam models,
spacetime is given merely by a combinatorial structure. In other
approaches spacetime is a net of causal relations (this is not
necessarily unrelated to the combinatorial structure I've mentioned
before).

i.o.

cosmolojosh

Apr24-10, 10:21 AM

What you said about gravitons AS SPACE ATOMS IS PRETTY MUCH LQG

tom.stoer

Apr24-10, 11:00 AM

There are a couple of ideas regarding a non-perturbative formulation of quantum gravity - LQG Is as far as I can see the most promising one. Most of them do not rely on gravitons; gravitons may emerge in some perturbative limit, but are not fundamental entities (like e.g. Photons in QED).

Vanadium 50

Apr24-10, 11:15 AM

This is a 6 year old thread; best to close it.