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Note:These pages make extensive use of the latest XHTML and CSS Standards. They ought to look great in any standards-compliant modern browser. Unfortunately, they will probably look horrible in older browsers, like Netscape 4.x and IE 4.x. Moreover, many posts use MathML, which is, currently only supported in Mozilla. My best suggestion (and you will thank me when surfing an ever-increasing number of sites on the web which have been crafted to use the new standards) is to upgrade to the latest version of your browser. If that's not possible, consider moving to the Standards-compliant and open-source Mozilla browser.

November 22, 2005

Wireless

Austin, as I’ve said, is WiFi heaven. But, then there are the times when you’re just plain out of range.

Last weekend, on the train from Seattle to Eugene I needed to access the 'Net. Amtrak, alas, has not added WiFi service to Business Class, but, fortunately, cell phone service works quite well. So I plugged the Bluetooth dongle into my iBook, and connected, wirelessly via cell phone to the UT dialup service. It was only 9600 baud, but we were on a train, after all.

Tonight, I found myself with 20 minutes to kill, waiting for my daughter’s rehearsal to finish at the Zach Scott Theater. Not really enough time to make a trip to the Schlotzky’s Deli down the street (with its free WiFi) worthwhile. So I pulled out my laptop, fired up the old Bluetooth and caught up on my email … right there in the parking lot.

Posted by distler at 2:42 AM | Permalink | Followups (2)

November 21, 2005

Squashed Bugs

Hard on the heels of fixing bug 228804, which, for years, had bedevilled the rendering of MathML in Mozilla/Mac, Yamashita Makoto has been busy fixing other bugs.

  • The disappearing minus sign bug is now fixed, so you don’t need to map U+2212 to some explicit choice of font, as I recommended previously.
  • The Symbol font is now recognized, and can be used with MathML.
  • Most surprisingly, Computer Modern Fonts can now be used with Mozilla (at least, in MacOSX 10.4).
    1. Download the CM/PS Fonts (and, if you want, the AMS/PS Fonts as well).
    2. Grab the screen fonts files from the Screen Fonts folder and drag it into the PS Fonts folder
    3. Drag the PS Fonts folder into /Library/Fonts or ~/Library/Fonts

Now, that sounds wonderful. But, alas, it is not a panacea. The nice calligraphic letters in CMSY10, or the blackboard bold letter in MSBM10, or the fraktur letters in EUFM10 still won’t work in Mozilla. There’s no way, apparently, to remap Plane-1 characters, so you still need to rely on a Unicode font like Code2001.

And there are more glitches. The circumflex accent gets rendered too high, when used in MathML. So do =, +, and × (but not −), because (apparently) they’re taken from some stupid fallback font, instead of one of the desired mathematical fonts.

Still, it’s real progress. And Makoto is even offering a version of Camino with MathML support enabled. So, if you want a MathML-capable Cocoa browser, Makoto’s your man …

Inline SVG

On a completely different topic, Firefox nightly builds are now SVG-enabled. That’s slightly old news. What’s new is that the native SVG support coexists nicely with the Adobe plugin. The native SVG support is missing some key features (no font-module support, for instance), so it doesn’t work properly with the SVG figures we use here at Musings. Fortunately, the Adobe plugin handles those just fine. On the other hand, the Adobe plugin doesn’t work at all with inline SVG (as used by … well, OK, nobody’s actually using inline SVG for anything other than the odd cutesy demo; but they could1), which is handled reasonably well by the native SVG support.

1 What with Opera 8 supporting SVG and support in the works in Safari, too, you’d think a few people might figure out some use for it.

Posted by distler at 12:41 AM | Permalink | Post a Comment

November 14, 2005

Swampy

One of the amusements of this past weekend was listening to Cumrun talk about the Swampland in perpetually-damp Eugene Oregon. I’ve discussed the subject here, before but what surprised me, when I asked him about it in person, was how modest his goals for the program are. He was very focussed on broad, qualitative features of vacua that could (or could not) arise in String Theory. More detailed, quantitative, questions he didn’t think were likely to be addressable in his framework. Perhaps, he was simply being cautious, sticking to things that might reasonably be proven in the near-term. But I think it’s important to state that more ambitious results are conceivable and — if String Theory is to usefully make contact with experiment — even necessary.

For concreteness, let us assume, it turns out that physics at low energies (below a few TeV) is described by the MSSM. This is a theory with no massless moduli, so any String vacua of this type are necessarily isolated. We don’t, currently, know of any String vacuum whose low-energy effective theory is precisely the MSSM (there are examples that come close). But many people confidently assert that the String Theory Landscape ought to contain a large number of such vacua. Let us be charitable and assume that they are correct.

Even so, these points form a set of measure zero in the MSSM parameter space1. The generic point in the MSSM moduli space is part of the Swampland! Let me say that again: the generic point in the MSSM moduli space does not have a consistent UV completion including gravity; only a set of points of measure zero are UV-consistent.

Moreover, it’s far from clear how those UV-consistent points are distributed within the MSSM parameter space.

  • Are they everywhere dense2?
  • Or are there “voids” where there are no, or only a few vacua?
  • Or do the points lie on, or near, a subspace of positive codimension?

Even if you believe that there are a large number of MSSM String Theory vacua, it’s an entirely separate, and far less plausible assertion that they are dense in the MSSM parameter space. Indeed, the whole point of the “Friendly Landscape” is that (if the Landscape is friendly) they are not dense, indeed, that they are peaked around some low-dimensional subspace of the parameter space3.

Finding genuinely realistic String vacua is a hard task. If we manage to find a large number of them, understanding how they are distributed within the relevant parameter space is yet another challenge. But it may be the one we ultimately need to face, to extract falsifiable predictions from String Theory.

1 I’m not sure what measure to assign to the parameter space, but it doesn’t really matter what you choose.

2 Strictly speaking, a finite set of points cannot be dense. What I really mean is that they cover the MSSM parameter space, to within the experimental accuracy of the ILC. The LHC may tell us that there is low-energy supersymmetry, but it is not going to be of much use in actually measuring the parameters of the MSSM.

3 The Landscape may well not be friendly. This is an open question, though one which is, in principle, addressable.

Posted by distler at 10:28 AM | Permalink | Followups (1)

November 8, 2005

Trackback Spam II

Back at the end of June, I reported that trackback spam directed against this site had soared to nearly 13,000/month. That was, by any measure, a pretty hefty amount of spam. You might well have wondered what has happened since then.

Continue reading “Trackback Spam II” ...
Posted by distler at 2:32 AM | Permalink | Followups (3)

November 7, 2005

Staring at the Tea Leaves

LEP closed down in 2000, to make way for the LHC. There were, towards the end, intriguing hints that there was, perhaps, a bit of a bump in the number of b-jet events, indicating the possibility of a Higgs. Arguments were made that the LEP run should be extended. But, in the end, LEP was shut down on schedule, and the consensus was that it had established a lower limit of m h>115 GeV.

Still, people continue to pore over the data and, recently, Dermisek and Gunion have challenged the above consensus. The limit seems to be rather neatly evaded i