Comments on: The Results of Resonance http://blogs.discovermagazine.com/cosmicvariance/2008/12/22/the-results-of-resonance/ Random samplings from a universe of ideas. Wed, 25 Nov 2009 01:09:37 -0600 http://wordpress.org/?v=2.8.4 hourly 1 By: Dmitry http://blogs.discovermagazine.com/cosmicvariance/2008/12/22/the-results-of-resonance/comment-page-1/#comment-54898 Dmitry Fri, 26 Dec 2008 13:41:13 +0000 http://blogs.discovermagazine.com/cosmicvariance/2008/12/22/the-results-of-resonance/#comment-54898 Hi Mark I think we came to pretty similar conclusions while studying <a href="http://arxiv.org/abs/hep-ph/0507096" rel="nofollow">dynamics of the effective equation of state during preheating</a>. Typically, what you get is prethermalization similar to the one seen in HIC - IR part of the dustribution n_k or k^3 n_k is nearly thermal (n_k resembles Rayleigh-Jeans) with some "effective temperature" which can be quite high immediately after the end of preheating (higher than 10^15 GeV). This "effective temperature" decreases with time much faster than according to the law T\sim 1/a one would naively expect, but there is still a chance to create heavy relics immediately after the end of preheating. As for dark matter - one way to generate large amount of it is to remove trilinear coupling terms between inflaton and matter scalar \chi from the Lagrangian. Then, the inflaton condensate has a rather large energy density after the end of parametric resonance regime (condensate cannot decay completely without trilinear terms). This energy density is so large typically, that the universe gets overclosed unless you introduce quite a bit of fine tuning into the model. Cheers, Dmitry. Hi Mark

I think we came to pretty similar conclusions while studying dynamics of the effective equation of state during preheating.

Typically, what you get is prethermalization similar to the one seen in HIC – IR part of the dustribution n_k or k^3 n_k is nearly thermal (n_k resembles Rayleigh-Jeans) with some “effective temperature” which can be quite high immediately after the end of preheating (higher than 10^15 GeV). This “effective temperature” decreases with time much faster than according to the law T\sim 1/a one would naively expect, but there is still a chance to create heavy relics immediately after the end of preheating.

As for dark matter – one way to generate large amount of it is to remove trilinear coupling terms between inflaton and matter scalar \chi from the Lagrangian. Then, the inflaton condensate has a rather large energy density after the end of parametric resonance regime (condensate cannot decay completely without trilinear terms). This energy density is so large typically, that the universe gets overclosed unless you introduce quite a bit of fine tuning into the model.

Cheers,
Dmitry.

]]> By: Neil B http://blogs.discovermagazine.com/cosmicvariance/2008/12/22/the-results-of-resonance/comment-page-1/#comment-54498 Neil B Thu, 25 Dec 2008 02:33:43 +0000 http://blogs.discovermagazine.com/cosmicvariance/2008/12/22/the-results-of-resonance/#comment-54498 Oh that's p + p ---> 3p + p bar. Oh that’s p + p —> 3p + p bar.

]]> By: Neil B http://blogs.discovermagazine.com/cosmicvariance/2008/12/22/the-results-of-resonance/comment-page-1/#comment-54496 Neil B Thu, 25 Dec 2008 02:27:15 +0000 http://blogs.discovermagazine.com/cosmicvariance/2008/12/22/the-results-of-resonance/#comment-54496 I've heard about a "maximum temperature" (maybe dep. on details) such that trying to raise the energy just causes particles to create more particles by collision energy, as in p + p = 4p and maybe some stray gamma etc. (so kinetic energy is about the mass-energy of nucleons, whatever temperature that is.) Yet that MT doesn't seem to figure in what I hear about "temperature" like in the early universe, which seems to go to unlimited values. What's up with that? Also, monopoles: seem to be nice for symmetry reasons, but: if you take the vector potential "A" field seriously (whatever that means), monopoles can't handle that in a tidy way - they need icky tails of A field trailing along, quite contrived. People tried to sort that out but it really isn't very natural looking is it? And if E field really is determined by Del phi - dA/dt, then the nice circular lines of E around moving monopoles wouldn't really be the deal, wouldn't that A-field rope or "seam" have to mess things up somewhere? Merry Christmas/ Happy Holidays. I’ve heard about a “maximum temperature” (maybe dep. on details) such that trying to raise the energy just causes particles to create more particles by collision energy, as in p + p = 4p and maybe some stray gamma etc. (so kinetic energy is about the mass-energy of nucleons, whatever temperature that is.) Yet that MT doesn’t seem to figure in what I hear about “temperature” like in the early universe, which seems to go to unlimited values. What’s up with that?

Also, monopoles: seem to be nice for symmetry reasons, but: if you take the vector potential “A” field seriously (whatever that means), monopoles can’t handle that in a tidy way – they need icky tails of A field trailing along, quite contrived. People tried to sort that out but it really isn’t very natural looking is it? And if E field really is determined by Del phi – dA/dt, then the nice circular lines of E around moving monopoles wouldn’t really be the deal, wouldn’t that A-field rope or “seam” have to mess things up somewhere?

Merry Christmas/ Happy Holidays.

]]> By: spyder http://blogs.discovermagazine.com/cosmicvariance/2008/12/22/the-results-of-resonance/comment-page-1/#comment-54188 spyder Tue, 23 Dec 2008 20:52:09 +0000 http://blogs.discovermagazine.com/cosmicvariance/2008/12/22/the-results-of-resonance/#comment-54188 Sorry John, i didn't quite spell that right, no wonder you are confused, as am i. That word should have been <i>semioticities</i>, the signs and symbols we use to construct semantical concepts such as words and meanings of them. Stephenson has created a new vocabulary, new words, new phrases--while trying his best to maintain continuity between the material most often discussed here in this blog, with his alternate universe. Sorry John, i didn’t quite spell that right, no wonder you are confused, as am i. That word should have been semioticities, the signs and symbols we use to construct semantical concepts such as words and meanings of them. Stephenson has created a new vocabulary, new words, new phrases–while trying his best to maintain continuity between the material most often discussed here in this blog, with his alternate universe.

]]> By: Mark http://blogs.discovermagazine.com/cosmicvariance/2008/12/22/the-results-of-resonance/comment-page-1/#comment-54130 Mark Tue, 23 Dec 2008 17:52:43 +0000 http://blogs.discovermagazine.com/cosmicvariance/2008/12/22/the-results-of-resonance/#comment-54130 What problem seems overconstrained? There should be no need to inflate to smooth out inhomogeneities due to the electroweak phase transition - not quite sure where that comes from. What problem seems overconstrained? There should be no need to inflate to smooth out inhomogeneities due to the electroweak phase transition – not quite sure where that comes from.

]]> By: Jonathan Vos Post http://blogs.discovermagazine.com/cosmicvariance/2008/12/22/the-results-of-resonance/comment-page-1/#comment-54122 Jonathan Vos Post Tue, 23 Dec 2008 17:19:14 +0000 http://blogs.discovermagazine.com/cosmicvariance/2008/12/22/the-results-of-resonance/#comment-54122 The problem seems overconstrained. Don't we first have to, as Abhay Ashtekar points out, have to get from smooth to quantized (Planck-length) space-time, perhaps with superinflation from t = 10^-45 seconds, then inflate to smooth out inhomogenieties of the electroweak phase transition at ten picoseconds? As my Physics professor wife Dr. Christine Carmichael points out in [unpublished stories and novel manuscript] the inhomogenieties may not be merely random, with a distribution to be sought in CMB, but the remnants of intelligent civilization of subatomic beings who were trying to build something lasting (i.e. Tower of Babel) but saw it all swept away in a tragedy at the beginning of time. There's a lovely science fiction poem that reinvented the same notion, by Tom Digby, and though neither of these two authors knew it, an earlkier and quite lovely science fiction short story by Benjamin Franklin: <a href="http://www.bartleby.com/109/1.html" rel="nofollow">The Ephemera: An Emblem of Human Life</a> The problem seems overconstrained. Don’t we first have to, as Abhay Ashtekar points out, have to get from smooth to quantized (Planck-length) space-time, perhaps with superinflation from t = 10^-45 seconds, then inflate to smooth out inhomogenieties of the electroweak phase transition at ten picoseconds?

As my Physics professor wife Dr. Christine Carmichael points out in [unpublished stories and novel manuscript] the inhomogenieties may not be merely random, with a distribution to be sought in CMB, but the remnants of intelligent civilization of subatomic beings who were trying to build something lasting (i.e. Tower of Babel) but saw it all swept away in a tragedy at the beginning of time. There’s a lovely science fiction poem that reinvented the same notion, by Tom Digby, and though neither of these two authors knew it, an earlkier and quite lovely science fiction short story by Benjamin Franklin:

The Ephemera: An Emblem of Human Life

]]> By: John http://blogs.discovermagazine.com/cosmicvariance/2008/12/22/the-results-of-resonance/comment-page-1/#comment-54067 John Tue, 23 Dec 2008 13:16:10 +0000 http://blogs.discovermagazine.com/cosmicvariance/2008/12/22/the-results-of-resonance/#comment-54067 I second most of that, but what--speaking of clarity in speaking to us laypeople--are semitocities? I second most of that, but what–speaking of clarity in speaking to us laypeople–are semitocities?

]]> By: spyder http://blogs.discovermagazine.com/cosmicvariance/2008/12/22/the-results-of-resonance/comment-page-1/#comment-53969 spyder Tue, 23 Dec 2008 03:21:40 +0000 http://blogs.discovermagazine.com/cosmicvariance/2008/12/22/the-results-of-resonance/#comment-53969 When somebody like myself (a non-physicist, non-scientist humanities academic), is an avid reader of this blog (and its predecessors), one actually begins to understand these sorts of discussion. This is due to three factors: the clearly stated to-the-layperson style and tone; the general joy of the physicists in communicating their life's work to others; and the on-going commentary and discussions of the material. All of you rock, and for this i am grateful and appreciative all the year round, not just during holidaze season. I was fascinated by this idea while reading Neal Stephenson's ANATHEM recently (and its associated materials). The book is filled with math and physics, all of which is reframed in new semitocities, yet retaining much of the same structures and constructs one finds in this blogsphere. Without the efforts of all of you, i would not have been able to sort through the material and discover that i had learned so much about cosmology, cosmogony, particle and quantum theory, etc.. Thanks for that alone. When somebody like myself (a non-physicist, non-scientist humanities academic), is an avid reader of this blog (and its predecessors), one actually begins to understand these sorts of discussion. This is due to three factors: the clearly stated to-the-layperson style and tone; the general joy of the physicists in communicating their life’s work to others; and the on-going commentary and discussions of the material. All of you rock, and for this i am grateful and appreciative all the year round, not just during holidaze season.

I was fascinated by this idea while reading Neal Stephenson’s ANATHEM recently (and its associated materials). The book is filled with math and physics, all of which is reframed in new semitocities, yet retaining much of the same structures and constructs one finds in this blogsphere. Without the efforts of all of you, i would not have been able to sort through the material and discover that i had learned so much about cosmology, cosmogony, particle and quantum theory, etc.. Thanks for that alone.

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