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	<title>Comments on: Aether Compactification</title>
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	<description>Random samplings from a universe of ideas</description>
	<pubDate>Tue, 07 Oct 2008 09:03:44 +0000</pubDate>
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		<item>
		<title>By: Do You Like Cat Fights? &#171; In Other Words</title>
		<link>http://cosmicvariance.com/2008/02/06/aether-compactification/#comment-311492</link>
		<dc:creator>Do You Like Cat Fights? &#171; In Other Words</dc:creator>
		<pubDate>Sun, 24 Feb 2008 23:19:21 +0000</pubDate>
		<guid isPermaLink="false">http://cosmicvariance.com/2008/02/06/aether-compactification/#comment-311492</guid>
		<description>[...] are positively boring! You want ugly, try String Theorists, vs. Anti-String Theorists. Now that&#8217;s one ugly cat [...]</description>
		<content:encoded><![CDATA[<p>[...] are positively boring! You want ugly, try String Theorists, vs. Anti-String Theorists. Now that&#8217;s one ugly cat [...]</p>
]]></content:encoded>
	</item>
	<item>
		<title>By: Jonathan Vos Post</title>
		<link>http://cosmicvariance.com/2008/02/06/aether-compactification/#comment-310479</link>
		<dc:creator>Jonathan Vos Post</dc:creator>
		<pubDate>Wed, 13 Feb 2008 11:09:11 +0000</pubDate>
		<guid isPermaLink="false">http://cosmicvariance.com/2008/02/06/aether-compactification/#comment-310479</guid>
		<description>Re: Blake Stacey, #33:

More Pynchon than Thompson, though your joke was nostalgic...:

"Against the Day", 
Page 566

In a dream...

This passage, describing Kit's dream of Umeki and the message it conveys, pulls together many of the main themes of Against the Day, tying things together in a way that Pynchon seldom does, almost as if he's providing a rather large piece of the puzzle to help the reader understand the novel:

    "Deep among the equations describing the behavor of light, field equations, Vector and Quaternion equations, lies a set of directions, an intinerary, a map to a hidden space. Double refraction appears again and again as a key element, permitting a view into a Creation set just to the side of this one, so close as to overlap, where the membrane between the worlds, in many places, has become too frail, too permeable, for safety.... Within the mirror, with the scalar term, within the daylit and obvious and taken-for-granted has always lain, as if in wait, the dark intinerary, the corrupted pilgrim's guide, the nameless Station before the first, in the lightless uncreated, where salvation does not yet exist." 

See references in Against the day also at:

Aether
55; 58; 132-133; 140; 306; 320; "sounds like light" 426; 458; 557; 565-66; 595; aka Akasa, 613; 620; aka Luminiferous aether ; Wikipedia article on Luminferous aether; 1911 Encyclopedia Britannica

Q-weapon
"Quaternion-ray weapons" 445; "intelligence of a Quaternionic Weapon, a means to unloose upon the world energies hitherto unimagined — hidden ... 'innocently,' inside the w term." 542; "Unfamiliar with the Tesla system and alarmed by the strengths of the electric and magnetic fields, de Decker's people naturally conflated this with those recent rumors of a Quaternion weapon..." 549; "as if this mysterious Q-weapon were a common firearm and he hoping the seller would allow him a few courtesy shots [emphasis added]" 557; "alive in Woevre's hands" 563; "Kit found himself alone with the enigmatic object, back inside the leather case. He slung it nonchalantly by its strap over one shoulder" 564; technical details, 564-565; 784;

Quaternions

130; In mathematics, quaternions are a non-commutative extension of complex numbers. They were first described by the Irish mathematician Sir William Rowan Hamilton in 1843 and applied to mechanics in three-dimensional space. At first, quaternions were regarded as pathological, because they disobeyed the commutative law ab = ba. Although they have been superseded in most applications by vectors, they still find uses in both theoretical and applied mathematics, in particular for calculations involving three-dimensional rotations. James Clerk Maxwell first published his famous theory describing electricity and magnetism as a set of twenty equations, but he was later able to reformulate it as four equations using quaternions. Heaviside translated these into four vector equations, the form typically taught in basic physics classes today. Heaviside's vector version is compatible with Einstein's special relativity, but the quaternion form is not; 131; 156; 511; 525; Wars, 526, 548; 533-34; 538-39; Quaternionic Weapon, 542; 557; 564; 590; Wikipedia entry; Quaternions at MathWorld; Hamiltonian quaternions at PlanetMath; Finding the site of Hamilton's inspiration (by mathematical physicist John Baez); Conspiracy-theory takes on mathematical history [1] [2] (by Tom Bearden, promotor of a dubious free energy machine); Primer on quaternions and their history

vacuum
60;

Vector
156; In mathematics, a vector space (or linear space) is a collection of objects (called vectors) that, informally speaking, may be scaled and added. More formally, a vector space is a set on which two operations, called (vector) addition and (scalar) multiplication, are defined and satisfy certain natural axioms. Vector spaces are the basic objects of study in linear algebra, and are used throughout mathematics, science, and engineering. 158; 165; vectorists, 534; and Monotony, 560; "in five dimensions" 675</description>
		<content:encoded><![CDATA[<p>Re: Blake Stacey, #33:</p>
<p>More Pynchon than Thompson, though your joke was nostalgic&#8230;:</p>
<p>&#8220;Against the Day&#8221;,<br />
Page 566</p>
<p>In a dream&#8230;</p>
<p>This passage, describing Kit&#8217;s dream of Umeki and the message it conveys, pulls together many of the main themes of Against the Day, tying things together in a way that Pynchon seldom does, almost as if he&#8217;s providing a rather large piece of the puzzle to help the reader understand the novel:</p>
<p>    &#8220;Deep among the equations describing the behavor of light, field equations, Vector and Quaternion equations, lies a set of directions, an intinerary, a map to a hidden space. Double refraction appears again and again as a key element, permitting a view into a Creation set just to the side of this one, so close as to overlap, where the membrane between the worlds, in many places, has become too frail, too permeable, for safety&#8230;. Within the mirror, with the scalar term, within the daylit and obvious and taken-for-granted has always lain, as if in wait, the dark intinerary, the corrupted pilgrim&#8217;s guide, the nameless Station before the first, in the lightless uncreated, where salvation does not yet exist.&#8221; </p>
<p>See references in Against the day also at:</p>
<p>Aether<br />
55; 58; 132-133; 140; 306; 320; &#8220;sounds like light&#8221; 426; 458; 557; 565-66; 595; aka Akasa, 613; 620; aka Luminiferous aether ; Wikipedia article on Luminferous aether; 1911 Encyclopedia Britannica</p>
<p>Q-weapon<br />
&#8220;Quaternion-ray weapons&#8221; 445; &#8220;intelligence of a Quaternionic Weapon, a means to unloose upon the world energies hitherto unimagined — hidden &#8230; &#8216;innocently,&#8217; inside the w term.&#8221; 542; &#8220;Unfamiliar with the Tesla system and alarmed by the strengths of the electric and magnetic fields, de Decker&#8217;s people naturally conflated this with those recent rumors of a Quaternion weapon&#8230;&#8221; 549; &#8220;as if this mysterious Q-weapon were a common firearm and he hoping the seller would allow him a few courtesy shots [emphasis added]&#8221; 557; &#8220;alive in Woevre&#8217;s hands&#8221; 563; &#8220;Kit found himself alone with the enigmatic object, back inside the leather case. He slung it nonchalantly by its strap over one shoulder&#8221; 564; technical details, 564-565; 784;</p>
<p>Quaternions</p>
<p>130; In mathematics, quaternions are a non-commutative extension of complex numbers. They were first described by the Irish mathematician Sir William Rowan Hamilton in 1843 and applied to mechanics in three-dimensional space. At first, quaternions were regarded as pathological, because they disobeyed the commutative law ab = ba. Although they have been superseded in most applications by vectors, they still find uses in both theoretical and applied mathematics, in particular for calculations involving three-dimensional rotations. James Clerk Maxwell first published his famous theory describing electricity and magnetism as a set of twenty equations, but he was later able to reformulate it as four equations using quaternions. Heaviside translated these into four vector equations, the form typically taught in basic physics classes today. Heaviside&#8217;s vector version is compatible with Einstein&#8217;s special relativity, but the quaternion form is not; 131; 156; 511; 525; Wars, 526, 548; 533-34; 538-39; Quaternionic Weapon, 542; 557; 564; 590; Wikipedia entry; Quaternions at MathWorld; Hamiltonian quaternions at PlanetMath; Finding the site of Hamilton&#8217;s inspiration (by mathematical physicist John Baez); Conspiracy-theory takes on mathematical history [1] [2] (by Tom Bearden, promotor of a dubious free energy machine); Primer on quaternions and their history</p>
<p>vacuum<br />
60;</p>
<p>Vector<br />
156; In mathematics, a vector space (or linear space) is a collection of objects (called vectors) that, informally speaking, may be scaled and added. More formally, a vector space is a set on which two operations, called (vector) addition and (scalar) multiplication, are defined and satisfy certain natural axioms. Vector spaces are the basic objects of study in linear algebra, and are used throughout mathematics, science, and engineering. 158; 165; vectorists, 534; and Monotony, 560; &#8220;in five dimensions&#8221; 675</p>
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	<item>
		<title>By: Lawrence B. Crowell</title>
		<link>http://cosmicvariance.com/2008/02/06/aether-compactification/#comment-310393</link>
		<dc:creator>Lawrence B. Crowell</dc:creator>
		<pubDate>Mon, 11 Feb 2008 13:22:12 +0000</pubDate>
		<guid isPermaLink="false">http://cosmicvariance.com/2008/02/06/aether-compactification/#comment-310393</guid>
		<description>This compactification scheme predicts the existence of light particles.  If this is an unknown particle then maybe the axion is a candidate.  Tight compactification, R very small in the above formula, would correspond to a massive particle --- maybe dark matter.

Quintessence and dark energy may involve a phase of the vacuum state, or at least this is what I suspect.  In fact dark matter might be local changes in this phase.  So called phantom energy might also be such a phase, though its amplitude or probability in the universe I think is near zero. 

Lawrence B. Crowell</description>
		<content:encoded><![CDATA[<p>This compactification scheme predicts the existence of light particles.  If this is an unknown particle then maybe the axion is a candidate.  Tight compactification, R very small in the above formula, would correspond to a massive particle &#8212; maybe dark matter.</p>
<p>Quintessence and dark energy may involve a phase of the vacuum state, or at least this is what I suspect.  In fact dark matter might be local changes in this phase.  So called phantom energy might also be such a phase, though its amplitude or probability in the universe I think is near zero. </p>
<p>Lawrence B. Crowell</p>
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	<item>
		<title>By: Neil B.</title>
		<link>http://cosmicvariance.com/2008/02/06/aether-compactification/#comment-310375</link>
		<dc:creator>Neil B.</dc:creator>
		<pubDate>Mon, 11 Feb 2008 00:55:54 +0000</pubDate>
		<guid isPermaLink="false">http://cosmicvariance.com/2008/02/06/aether-compactification/#comment-310375</guid>
		<description>OK, what about "quintessence"?  Any way to work that in, how does it relate to dark energy in general etc? I get the impression, Q isn't just a mere synonym for DE in general. I wish I'd thought to ask earlier, but anyone LMK if have good scoop.</description>
		<content:encoded><![CDATA[<p>OK, what about &#8220;quintessence&#8221;?  Any way to work that in, how does it relate to dark energy in general etc? I get the impression, Q isn&#8217;t just a mere synonym for DE in general. I wish I&#8217;d thought to ask earlier, but anyone LMK if have good scoop.</p>
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	</item>
	<item>
		<title>By: Blake Stacey</title>
		<link>http://cosmicvariance.com/2008/02/06/aether-compactification/#comment-310297</link>
		<dc:creator>Blake Stacey</dc:creator>
		<pubDate>Fri, 08 Feb 2008 17:04:43 +0000</pubDate>
		<guid isPermaLink="false">http://cosmicvariance.com/2008/02/06/aether-compactification/#comment-310297</guid>
		<description>Why am I suddenly getting a Hunter S. Thompson voice in my head?

"There is nothing in the world more helpless and compactified than a man in the depths of an aether binge. . . ."</description>
		<content:encoded><![CDATA[<p>Why am I suddenly getting a Hunter S. Thompson voice in my head?</p>
<p>&#8220;There is nothing in the world more helpless and compactified than a man in the depths of an aether binge. . . .&#8221;</p>
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		<title>By: Moshe</title>
		<link>http://cosmicvariance.com/2008/02/06/aether-compactification/#comment-310296</link>
		<dc:creator>Moshe</dc:creator>
		<pubDate>Fri, 08 Feb 2008 17:04:26 +0000</pubDate>
		<guid isPermaLink="false">http://cosmicvariance.com/2008/02/06/aether-compactification/#comment-310296</guid>
		<description>Regarding extra dimensions. the existing paradigm in fundamental physics is that things becomes simpler, more symmetric and more unique at short distances, and complexity arises in the process of symmetry breaking. If this continues we expect new degrees of freedom at shorter distances and new symmetries to relate them. Extra dimension is just a way of organizing those new degrees of freedom (as harmonics in some space) which works for a large class of models. The new symmetries are then rotations in those extra dimensions. Having new degrees of freedom without new symmetries I find less motivated, but it is a matter of taste.</description>
		<content:encoded><![CDATA[<p>Regarding extra dimensions. the existing paradigm in fundamental physics is that things becomes simpler, more symmetric and more unique at short distances, and complexity arises in the process of symmetry breaking. If this continues we expect new degrees of freedom at shorter distances and new symmetries to relate them. Extra dimension is just a way of organizing those new degrees of freedom (as harmonics in some space) which works for a large class of models. The new symmetries are then rotations in those extra dimensions. Having new degrees of freedom without new symmetries I find less motivated, but it is a matter of taste.</p>
]]></content:encoded>
	</item>
	<item>
		<title>By: Sean</title>
		<link>http://cosmicvariance.com/2008/02/06/aether-compactification/#comment-310295</link>
		<dc:creator>Sean</dc:creator>
		<pubDate>Fri, 08 Feb 2008 16:20:05 +0000</pubDate>
		<guid isPermaLink="false">http://cosmicvariance.com/2008/02/06/aether-compactification/#comment-310295</guid>
		<description>Rhys, I don't think that "better than 50-50 odds" translates easily into "such great confidence."  But I think that some version of string theory is probably correct, and string theory requires extra dimensions.</description>
		<content:encoded><![CDATA[<p>Rhys, I don&#8217;t think that &#8220;better than 50-50 odds&#8221; translates easily into &#8220;such great confidence.&#8221;  But I think that some version of string theory is probably correct, and string theory requires extra dimensions.</p>
]]></content:encoded>
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	<item>
		<title>By: CMT</title>
		<link>http://cosmicvariance.com/2008/02/06/aether-compactification/#comment-310289</link>
		<dc:creator>CMT</dc:creator>
		<pubDate>Fri, 08 Feb 2008 14:40:54 +0000</pubDate>
		<guid isPermaLink="false">http://cosmicvariance.com/2008/02/06/aether-compactification/#comment-310289</guid>
		<description>Spayced,

You do realize that most scientists do exactly what you want them to do? And in fact, so do most physicists?</description>
		<content:encoded><![CDATA[<p>Spayced,</p>
<p>You do realize that most scientists do exactly what you want them to do? And in fact, so do most physicists?</p>
]]></content:encoded>
	</item>
	<item>
		<title>By: Rhys</title>
		<link>http://cosmicvariance.com/2008/02/06/aether-compactification/#comment-310285</link>
		<dc:creator>Rhys</dc:creator>
		<pubDate>Fri, 08 Feb 2008 12:45:25 +0000</pubDate>
		<guid isPermaLink="false">http://cosmicvariance.com/2008/02/06/aether-compactification/#comment-310285</guid>
		<description>Sean: "I would give better than 50-50 odds on the existence of extra dimensions..."


I would probably take up that bet if it was possible for it to be settled in my favour!  Why do you have such great confidence in the existence of extra dimensions?</description>
		<content:encoded><![CDATA[<p>Sean: &#8220;I would give better than 50-50 odds on the existence of extra dimensions&#8230;&#8221;</p>
<p>I would probably take up that bet if it was possible for it to be settled in my favour!  Why do you have such great confidence in the existence of extra dimensions?</p>
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	<item>
		<title>By: Lawrence B. Crowell</title>
		<link>http://cosmicvariance.com/2008/02/06/aether-compactification/#comment-310267</link>
		<dc:creator>Lawrence B. Crowell</dc:creator>
		<pubDate>Fri, 08 Feb 2008 02:06:14 +0000</pubDate>
		<guid isPermaLink="false">http://cosmicvariance.com/2008/02/06/aether-compactification/#comment-310267</guid>
		<description>Maybe this is a way of deriving the axion particle.  A compactification [itex]n\hbar/Rc[/itex] for R large might create just the right particle mass for the CP-preserving field with QCD.  In E_8 the two exceptional groups F_4 and G_2 or

[tex]
e_8~=~f_4~+~g_2~+~26\times 7
[/tex]

where f_4 contains the so(3,1) for gravity and the so(4) for weak interactions with so(4) = su(2) + su(2) for the left and right handed parts.  CP violation leaves the left su(2), but we have no analogous handedness breaking in QCD.  Then to balance everything out maybe large scale compactification in an S-duality sense leaves generates a tiny mass field ---- the axion, and there is a dual field which compactifies on a tiny scale ~ near L_p.  This would "balance" the role of CP violation in the gravitation plus weak F_4 sector with the hypercharge plus QCD G_2 sector.

Lawrence B. Crowell</description>
		<content:encoded><![CDATA[<p>Maybe this is a way of deriving the axion particle.  A compactification [itex]n\hbar/Rc[/itex] for R large might create just the right particle mass for the CP-preserving field with QCD.  In E_8 the two exceptional groups F_4 and G_2 or</p>
<p><img src='/latexrender/pictures/316d035244cb71e8e6ef93137e19c74e.gif' title='&#13;&#10;e_8~=~f_4~+~g_2~+~26\times 7&#13;&#10;' alt='&#13;&#10;e_8~=~f_4~+~g_2~+~26\times 7&#13;&#10;' align=absmiddle/></p>
<p>where f_4 contains the so(3,1) for gravity and the so(4) for weak interactions with so(4) = su(2) + su(2) for the left and right handed parts.  CP violation leaves the left su(2), but we have no analogous handedness breaking in QCD.  Then to balance everything out maybe large scale compactification in an S-duality sense leaves generates a tiny mass field &#8212;- the axion, and there is a dual field which compactifies on a tiny scale ~ near L_p.  This would &#8220;balance&#8221; the role of CP violation in the gravitation plus weak F_4 sector with the hypercharge plus QCD G_2 sector.</p>
<p>Lawrence B. Crowell</p>
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		<title>By: spayced</title>
		<link>http://cosmicvariance.com/2008/02/06/aether-compactification/#comment-310255</link>
		<dc:creator>spayced</dc:creator>
		<pubDate>Thu, 07 Feb 2008 13:37:11 +0000</pubDate>
		<guid isPermaLink="false">http://cosmicvariance.com/2008/02/06/aether-compactification/#comment-310255</guid>
		<description>I hate this crap. When we start getting into scientists saying "I believe..." we have a problem. This is all great fun math gymnastics, but means nothing practicality wise as it is based on amazing calculations not observation, evidence, or anything resembling proof.

 http://www.gdargaud.net/Humor/Pics/string_theory.png

Scientists used to look at something in nature that we had not understood, like light for instance. They would come up with ideas about how it would work, then go to observation to confirm and calculations for exactness. Now we go from calculations to theories and back again, veering so far from observable reality and the other steps, primarily confirmation before continuing, the result is nonsense. I know all of you mean well (I'm not saying all of these people are wrong) it's just the process of coming up with raw theory is not science.</description>
		<content:encoded><![CDATA[<p>I hate this crap. When we start getting into scientists saying &#8220;I believe&#8230;&#8221; we have a problem. This is all great fun math gymnastics, but means nothing practicality wise as it is based on amazing calculations not observation, evidence, or anything resembling proof.</p>
<p> <a href="http://www.gdargaud.net/Humor/Pics/string_theory.png" rel="nofollow">http://www.gdargaud.net/Humor/Pics/string_theory.png</a></p>
<p>Scientists used to look at something in nature that we had not understood, like light for instance. They would come up with ideas about how it would work, then go to observation to confirm and calculations for exactness. Now we go from calculations to theories and back again, veering so far from observable reality and the other steps, primarily confirmation before continuing, the result is nonsense. I know all of you mean well (I&#8217;m not saying all of these people are wrong) it&#8217;s just the process of coming up with raw theory is not science.</p>
]]></content:encoded>
	</item>
	<item>
		<title>By: Odani the Multi-talented Undergrad</title>
		<link>http://cosmicvariance.com/2008/02/06/aether-compactification/#comment-310250</link>
		<dc:creator>Odani the Multi-talented Undergrad</dc:creator>
		<pubDate>Thu, 07 Feb 2008 07:12:57 +0000</pubDate>
		<guid isPermaLink="false">http://cosmicvariance.com/2008/02/06/aether-compactification/#comment-310250</guid>
		<description>Caltech?  Not UW-Madison?  You sure of that?

Oh.  These genetics posts did seem kind of weird.  I thought it was just me--turns out that you weren't really you.  

http://www.genetics.wisc.edu/faculty/profile.php?id=98</description>
		<content:encoded><![CDATA[<p>Caltech?  Not UW-Madison?  You sure of that?</p>
<p>Oh.  These genetics posts did seem kind of weird.  I thought it was just me&#8211;turns out that you weren&#8217;t really you.  </p>
<p><a href="http://www.genetics.wisc.edu/faculty/profile.php?id=98" rel="nofollow">http://www.genetics.wisc.edu/faculty/profile.php?id=98</a></p>
]]></content:encoded>
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	<item>
		<title>By: Haelfix</title>
		<link>http://cosmicvariance.com/2008/02/06/aether-compactification/#comment-310249</link>
		<dc:creator>Haelfix</dc:creator>
		<pubDate>Thu, 07 Feb 2008 06:10:09 +0000</pubDate>
		<guid isPermaLink="false">http://cosmicvariance.com/2008/02/06/aether-compactification/#comment-310249</guid>
		<description>It would be nontrivial to figure out a mechanism for fixing one direction like that so exactly, at least so long as we don't relegate the dynamics to the very early universe. 

The other issue I think at first glance is that while its true the zero modes might spread out and average out over space in the infinite volume limit, it probably need not be true for V finite.   Also, it would be nice to to reconstruct the solution for a nontrivial metric with compact 3D spacial topology (say a closed FRW universe).</description>
		<content:encoded><![CDATA[<p>It would be nontrivial to figure out a mechanism for fixing one direction like that so exactly, at least so long as we don&#8217;t relegate the dynamics to the very early universe. </p>
<p>The other issue I think at first glance is that while its true the zero modes might spread out and average out over space in the infinite volume limit, it probably need not be true for V finite.   Also, it would be nice to to reconstruct the solution for a nontrivial metric with compact 3D spacial topology (say a closed FRW universe).</p>
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	<item>
		<title>By: onymous</title>
		<link>http://cosmicvariance.com/2008/02/06/aether-compactification/#comment-310247</link>
		<dc:creator>onymous</dc:creator>
		<pubDate>Thu, 07 Feb 2008 05:55:29 +0000</pubDate>
		<guid isPermaLink="false">http://cosmicvariance.com/2008/02/06/aether-compactification/#comment-310247</guid>
		<description>&lt;i&gt;onymous, that number doesn’t appear directly in the action; it’s a ratio of two different mass scales.&lt;/i&gt;

But if you have physics that generates the operator coupling your Lorentz-violating vector to the kinetic term of your fields, wouldn't you tend to expect to also generate operators coupling it to other terms? It just seems a little unnatural. And if it appears in front of other terms, it really can play the role of a large coupling.</description>
		<content:encoded><![CDATA[<p><i>onymous, that number doesn’t appear directly in the action; it’s a ratio of two different mass scales.</i></p>
<p>But if you have physics that generates the operator coupling your Lorentz-violating vector to the kinetic term of your fields, wouldn&#8217;t you tend to expect to also generate operators coupling it to other terms? It just seems a little unnatural. And if it appears in front of other terms, it really can play the role of a large coupling.</p>
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		<title>By: George Musser</title>
		<link>http://cosmicvariance.com/2008/02/06/aether-compactification/#comment-310246</link>
		<dc:creator>George Musser</dc:creator>
		<pubDate>Thu, 07 Feb 2008 04:24:33 +0000</pubDate>
		<guid isPermaLink="false">http://cosmicvariance.com/2008/02/06/aether-compactification/#comment-310246</guid>
		<description>Sean, wasn't one of Ted Jacobson's concerns that a Lorentz-violating field could permit multiple event horizons and violations of the Second Law?
George</description>
		<content:encoded><![CDATA[<p>Sean, wasn&#8217;t one of Ted Jacobson&#8217;s concerns that a Lorentz-violating field could permit multiple event horizons and violations of the Second Law?<br />
George</p>
]]></content:encoded>
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	<item>
		<title>By: Sean</title>
		<link>http://cosmicvariance.com/2008/02/06/aether-compactification/#comment-310244</link>
		<dc:creator>Sean</dc:creator>
		<pubDate>Thu, 07 Feb 2008 04:10:37 +0000</pubDate>
		<guid isPermaLink="false">http://cosmicvariance.com/2008/02/06/aether-compactification/#comment-310244</guid>
		<description>onymous, that number doesn't appear directly in the action; it's a ratio of two different mass scales.  In particular, the coupling of excitations of the vector to other fields is actually suppressed by a (potentially) large number.  But it's certainly a good question why such a number would appear.</description>
		<content:encoded><![CDATA[<p>onymous, that number doesn&#8217;t appear directly in the action; it&#8217;s a ratio of two different mass scales.  In particular, the coupling of excitations of the vector to other fields is actually suppressed by a (potentially) large number.  But it&#8217;s certainly a good question why such a number would appear.</p>
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		<title>By: sammyo</title>
		<link>http://cosmicvariance.com/2008/02/06/aether-compactification/#comment-310242</link>
		<dc:creator>sammyo</dc:creator>
		<pubDate>Thu, 07 Feb 2008 03:19:59 +0000</pubDate>
		<guid isPermaLink="false">http://cosmicvariance.com/2008/02/06/aether-compactification/#comment-310242</guid>
		<description>Woo, 'Jumpers' in real life soon!   ;-)</description>
		<content:encoded><![CDATA[<p>Woo, &#8216;Jumpers&#8217; in real life soon!   <img src='http://cosmicvariance.com/wp-includes/images/smilies/icon_wink.gif' alt=';-)' class='wp-smiley' /></p>
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		<title>By: onymous</title>
		<link>http://cosmicvariance.com/2008/02/06/aether-compactification/#comment-310241</link>
		<dc:creator>onymous</dc:creator>
		<pubDate>Thu, 07 Feb 2008 03:18:31 +0000</pubDate>
		<guid isPermaLink="false">http://cosmicvariance.com/2008/02/06/aether-compactification/#comment-310241</guid>
		<description>&lt;i&gt;the coupling &#945;i has to be at least 1015, which any particle physicist will tell you is an unnaturally big number&lt;/i&gt;

In particular, why doesn't one run into intractable nonperturbative physics whenever this coupling is much greater than 1?</description>
		<content:encoded><![CDATA[<p><i>the coupling &alpha;i has to be at least 1015, which any particle physicist will tell you is an unnaturally big number</i></p>
<p>In particular, why doesn&#8217;t one run into intractable nonperturbative physics whenever this coupling is much greater than 1?</p>
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		<title>By: Neil B.</title>
		<link>http://cosmicvariance.com/2008/02/06/aether-compactification/#comment-310239</link>
		<dc:creator>Neil B.</dc:creator>
		<pubDate>Thu, 07 Feb 2008 02:06:25 +0000</pubDate>
		<guid isPermaLink="false">http://cosmicvariance.com/2008/02/06/aether-compactification/#comment-310239</guid>
		<description>So why does the universe need to hide other large dimensions anyway, or does it? Many say, there is no inherent physical need for space to have three large dimensions (need, to avoid contradiction issues, not about anthropic suitability.)  But can it seriously be said that no quirky problems of physical consistency would arise (assuming a logical extrapolation or analogy to our laws, I presume - is that unambiguous however?) in universes with other than 3 + 1 dimensions? Think about for example trying to apply dimensional analysis (of the MLT type, so as not to confuse with "number of space dimensions") to the analogous expressions for radiation reaction, radiation power, etc. I have fiddled with that and it doesn't seem to work right. Some have noted there need to be special constants in other kinds of spaces, even for banal things like electromagnetic radiation, which make those spaces appear "contrived" (i.e., they need special propping up "by hand" to avoid logical loose ends perhaps. Well, ours is contrived too in some ways I suppose.)</description>
		<content:encoded><![CDATA[<p>So why does the universe need to hide other large dimensions anyway, or does it? Many say, there is no inherent physical need for space to have three large dimensions (need, to avoid contradiction issues, not about anthropic suitability.)  But can it seriously be said that no quirky problems of physical consistency would arise (assuming a logical extrapolation or analogy to our laws, I presume - is that unambiguous however?) in universes with other than 3 + 1 dimensions? Think about for example trying to apply dimensional analysis (of the MLT type, so as not to confuse with &#8220;number of space dimensions&#8221;) to the analogous expressions for radiation reaction, radiation power, etc. I have fiddled with that and it doesn&#8217;t seem to work right. Some have noted there need to be special constants in other kinds of spaces, even for banal things like electromagnetic radiation, which make those spaces appear &#8220;contrived&#8221; (i.e., they need special propping up &#8220;by hand&#8221; to avoid logical loose ends perhaps. Well, ours is contrived too in some ways I suppose.)</p>
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		<title>By: Moshe</title>
		<link>http://cosmicvariance.com/2008/02/06/aether-compactification/#comment-310238</link>
		<dc:creator>Moshe</dc:creator>
		<pubDate>Thu, 07 Feb 2008 02:04:26 +0000</pubDate>
		<guid isPermaLink="false">http://cosmicvariance.com/2008/02/06/aether-compactification/#comment-310238</guid>
		<description>In addition to what Sean said, it is really difficult to make sense of physics with more than one time direction, it is not clear what you mean by very basic notions such  as time evolution, quantum mechanical probabilities, configuration or phase space etc. Despite the exotic sounding ``extra dimensions`, they represent no conceptual change, every physicist would know immediately what to calculate and how to interpret the results.

(I think Bars calling his program two-time physics is a little tongue in cheek, certainly there is no additional physical time direction there, one of the time directions is always gauge fixed. Allowing thisd extra redundancy is useful mathematical trick though.)</description>
		<content:encoded><![CDATA[<p>In addition to what Sean said, it is really difficult to make sense of physics with more than one time direction, it is not clear what you mean by very basic notions such  as time evolution, quantum mechanical probabilities, configuration or phase space etc. Despite the exotic sounding &#8220;extra dimensions`, they represent no conceptual change, every physicist would know immediately what to calculate and how to interpret the results.</p>
<p>(I think Bars calling his program two-time physics is a little tongue in cheek, certainly there is no additional physical time direction there, one of the time directions is always gauge fixed. Allowing thisd extra redundancy is useful mathematical trick though.)</p>
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