Arcadian Functor

occasional meanderings in physics' brave new world

My Photo
Name:
Location: New Zealand

Marni D. Sheppeard

Tuesday, April 01, 2008

Greetings

Greetings from Wanaka (not an April fools' joke).

8 Comments:

Blogger nige said...

Greetings to New Zealand! It's off topic, I suppose, but what happened about the open air physics conference you were planning? It was supposed to be held sometime this year, and it's already Spring here (Autumn where you are, I expect)? You specifically invited, I recall, Carl Brannen, Tony Smith, Louise Riofrio, and others.

Has this event occurred, is it still in the pipeline, or are you too busy now to host it? It would be fun to visit New Zealand (although the flight would be awful I imagine, however some sleeping tablets - plus aspirin to avoid any risk of thrombosis - would probably make it survivable).

Also off topic, I've just found the answer to a vital puzzle that was driving me crazy over the Standard Model, which I couldn't resolve from any of the books (Weinberg, Zee, Ryder, etc.). I found it in the latest edition of an old book by Frank Close.

It turns out that U(1) can't correctly predict electromagnetism by itself, it's gauge boson B_0 has to be mixed with the W_0 gauge boson from SU(2) to give the weak Z_0 and the electromagnetic gauge boson. This is pretty interesting, because the oversimplified discussions say U(1) is electromagnetic interaction and SU(2) is weak interaction. In order for the simplified explanation of the Standard Model to be true, where B_0 is the photon (field quanta of electromagnetism) and W_0 of SU(2) is the Z_0 weak neutral gauge boson, the Weinberg mixing angle between the vectors representing Z_0 and W_0 would have to be zero, when in fact it's 25 degrees empirically.

It's exciting to find that U(1) and SU(2) field quanta are so well and truly "mixed up" in the Standard Model, instead of separately representing electromagnetic and weak interactions. This seems to be played down, or covered up, in all the other books I've read because it's an unexplained fix-up of the Standard Model, and not something people are particularly proud of, a little bit like having a theory that uses epicycles. However, the real challenge is to replace it with something that corresponds to similarly accurate field lagrangians, while requiring less speculation and ad hoc fixes, and making additional predictions. I think it's extremely attractive to focus on the possibility of replacing U(1) x SU(2) + Higgs mechanism with an SU(2) which allows the 3 field quanta of SU(2) to exist as massless electromagnetic and gravitational field quanta at low energy, not just as massive weak gauge bosons at low energy. The way that mass is coupled to those 3 field quanta of SU(2) to produce weak gauge bosons at low energy can account for chiral symmetry. The deep problem here is figuring out in detail the mass-giving field required to supply mass to the right proportion of field quanta at low energy in such a way that they only act on left-handed charges. I think that this can only be accomplished by fully understanding the Standard Model lagrangian and Higgs field, and seeing how these need to be modified. As far as I'm concerned, the electric field around an electron is negative because it's carried by charged (negative) field quanta, while the electric field around a proton is positive because it's mediated by positive field quanta. We never get to see the core of the electron, because we don't have high enough energy collisions: we only observed the "charge" of the electric field, and what we are observing is therefore the charge of the field quanta which mediate the electric field. In my view, the electrically neutral photon is a 50:50 mixing between negative and positive electromagnetic field quanta. You can't get a neutral photon to mediate a charged field. The mainstream idea of finding that electromagnetic field quanta have 4 polarizations, not 2 polarizations (like ordinary photons of light) is correct really, but the 2 additional polarizations are the two kinds of net electric charge the electromagnetic gauge boson can carry. Because charged field quanta are exchanged between similar charges, but will be absorbed by unlike charges, two electrons will tend to repel because they're exchanging negative field quanta with one another, so the impulses are knocking each electron apart from the other (the inbound electromagnetic exchange radiation from distant charges in the surrounding universe is redshifted to low energy, so can't cancel out this net "repulsion"). In the case of unlike charges, they shield one another rather than xchanging field quanta, so they get pushed together by shielding each other on facing sides from exchange radiation from the surrounding universe. In this mechanism, by adding up vectors from all directions for net energy flow rates, you can actually show that the acceleration of two unit similar charges away from one another is identical to the attractive acceleration of two unit opposite charges. Both forces are basically powered by the equilibrium of exchange of field quanta with the surrounding universe, and the proximity of two local charges just creates an asymmetry which results in the attraction of unlike charges and repulsion of unlike charges. Because there are two types of electric charge, and alternating positive and negative charges can be found by a large number of different 'drunkard's walks' of electromagnetic gauge bosons between all the fundamental particles in the universe (like a series of alternating positive and negative capacitor plates with a vacuum dielectric between them), it follows that the net electromagnetic force will be bigger than the gravitational force (which with only one kind of gravitational charge, can't be multiplied in this way) by a vector sum of the drunkard's walk between positive and negative charges in the universe, about the square root of the number of atoms, ie (10^80)^0.5 = 10^40.

It's nice how simply this stuff works out, but it's a daunting challenge to investigate a complete replacement of the electroweak sector of the Standard Model by a theory which includes gravity and sorts out all the ad hoc problems with the Standard Model. I'm up to my neck with IT problems at the moment and it will be several weeks before I have any more free time to look at this.

April 02, 2008 5:09 AM  
Blogger CarlBrannen said...

As someone who hoped to get that open air conference, I'll answer Nigel. From my point of view, the big problem is we don't have any money. If we did decide on a place, there isn't any way for us to pay for the travel expenses.

April 02, 2008 9:00 AM  
Blogger L. Riofrio said...

Beautiful view! The air looks very clean, just the thing to clear the mind.

This year will have about 7 conferences, I hope to include NZ even if it is a conference for two. Carl should consider "Crisis in Cosmology" September 7-11 in Port Angeles WA, right in the neighbourhood.

April 02, 2008 5:13 PM  
Blogger nige said...

Carl,

thanks for replying. I agree it's very expensive to travel all the way to New Zealand and back for a conference.

I don't know what value for money you get on distant air travel when booking from the USA, but I took a look at some prices before making my comment, and www.airnewzealand.co.uk offers tickets starting from about 700 pounds, although there are restrictions on which flights these fares apply to.

This is still very expensive, and thought of paying a really large sum of money to spend 12 or more hours cramped in an economy flight (probably seated beside a "courting couple", as usually occurs when I fly anywhere alone) is not exactly pleasant, but it might be a possibility.

I've actually never been more than 4 hours flying from the UK, athough I know three different girls who saved up just about all their salaries from part time jobs while at college, and spent it on touring Australia while still teenagers. So financially it is in part a matter of priorities, although I'm not particularly keen to sell my car to bankroll this conference myself at this stage (partly because I don't have complete paper to present myself at present!).

A messier option in the short term might be to try organising a physics conference over the internet, if that could be done in a professional way. On the negative side, everyone would be in different time zones, and it's not clear how such a web conference could be made to look professional. On the positive side, if an internet based conference did work out, it would potentially be open to a large number of people.

April 03, 2008 8:28 AM  
Anonymous a quantum diaries survivor said...

Hi Kea,

nice pic, did you take it yourself ? Is the thing in the middle the famous Wanaka lake monster or just a plain island ?

As re: open air conference, why not organizing it as a internet event ? with a 10$ webcam and the free software (vrvs.org, now evo) it can be run easily...

Cheers
T.

April 09, 2008 12:34 AM  
Blogger Kea said...

Hi Tommaso. Yes, tis an island, not a monster. Nice picnic spot reachable by kayak. The locals are not very superstitious down this way.

April 09, 2008 11:05 AM  
Anonymous a quantum diaries survivor said...

I see....

I also have to apologize from not seeing that the idea of a internet conference had been put forth before! Nige you write too much! :)

Cheers,
T.

April 10, 2008 4:21 AM  
Blogger Kea said...

Tommaso, I think the idea of a web conference is excellent, and if money was my only problem, I'd get right onto it. BTW, I still don't own a camera - hence the lack of holiday shots.

April 10, 2008 9:58 AM  

Post a Comment

<< Home