occasional meanderings in physics' brave new world

Name:
Location: New Zealand

Marni D. Sheppeard

## Monday, February 19, 2007

### M Theory Lesson 14

The higher categorical parity cube is a broken pentagon, such as the one that appeared in operad theory. It is simply the diagram
The top face really looks like
if we use trees to label choices of bracketings. Carl Brannen's idempotents for lepton masses are also labelled by the parity cube, which describes three directions in space as well as three generations. It is nice to know that this agrees with the number of quark generations that we get by calculating an Euler characteristic for a gluon orbifold modelled by twistors.

CarlBrannen said...

Of course I don't know anything about these things. From the way they're labeled, I would think that they seem more similar to the idempotent structure of 3x3 complex matrices. I.e. eight states, top is 1, bottom is 0, three primitive states and three states given by sums of pairs of different primitives.

The cube that gives the elementary particles is from a more complicated idempotent structure, one that has 1 on the top (not shown), then 8 primitives (shown as the corners of a cube), then 28 given by sums of different primitives (not shown), and etc. through the rest of the Pascal triangle for (1+x)^8.

Meanwhile, my Java simulation of Stern-Gerlach filters is slowly progressing. With a little luck I should have results in a day or two.

February 19, 2007 1:57 PM
Kea said...

Yes, it's the 3x3 complex matrices that I'm thinking of here. Good luck with the simulation.

February 19, 2007 2:41 PM
a quantum diaries survivor said...

Hi Kea,

as much as I would love to understand what you sometimes start talking about here, my head usually explodes in the fashion of the aliens in "Mars Attacks!"...

Darn. They should warn would-be physicists that there is really no chance that they will understand things once they get a degree. They need seven.

So how do you get the number of generations, for the rest of us ?

Cheers,
T.

February 21, 2007 1:28 AM
Kea said...

So how do you get the number of generations, for the rest of us?

Tommaso, that's what this whole blog is about. We are getting there slowly. Interestingly, at my last conference talk there was a guy who has worked on the existence of a fourth (sterile) neutrino. We await the experimental conclusions. Only one of us can be right.

February 21, 2007 9:23 AM