Saturday March 29, 2008 5:20 am Lethbridge, Alberta

This page last updated on: Sunday, April 20, 2008 9:25 AM

It is -3 C with a high forecast of +1 C. Sunrise 7:14 Sunset 19:58 Hours of daylight: 12:44

A. Morning Musings

The forecast is improving, with only about 5 cm predicted for later today.

I am now listening to a CD called The Book of Kings by an artist called Zaza which I bought a couple of years ago. This is music that is based on the book of the same title that I received yesterday. A special way to begin the morning. That, plus Rumi and coffee.

The Rumi reading for this morning is a metaphor about water and rivers drying up. It is a perfect match for the news item on the Australian web site this morning that describes the problems with the Murray River.

My primary goal today will be to finish reading my quantum physics book.

Learning Category	Planned Activities for Today	Time
Literature	Begin morning with a Rumi reading
Science	Complete reading "Quantum: A Guide for the Perplexed" by Jim Al-Khalili	1 hr
Literature	Begin reading "South of the Border, West of the Sun" by Haruki Murakami	1 hr
Mathematics	Begin reading "Symmetry" by Marcus du Sautoy	1 hr

B. Actual Learning Activities

6:00 am

Quantum: A Guide for the Perplexed (2003)

Jim Al-Khalili

Chapter 8 The Search for the Ultimate Theory

I skim-read this chapter yesterday.

"The quest for the ultimate truths is always a quest for beauty and simplicity. It does appear that the multitude of phenomena we observe around us, whether on Earth or deduced from the light of a distant star, are ultimately explained by a remarkably small number of fundamental theories. The whole of classical mechanics is explainable by Newton's laws of motion and forces, and Einstein's theories of relativity improved on this; both electricity and magnetism turn out to be two manifestations of the same electromagnetic force; and of course the behavior of all subatomic particles is described by quantum mechanics." [p. 190]
"So 20th-century physicists needed to do more than simply find and classify all fundamental particles. They needed to understand the way these particles interacted with each other and the origin of the forces between them. And if there were different types of forces, did they have a common origin? The quantum mechanics of the 1920s was really just the first step along this path." [p. 190]
"Most phenomena we see around us and care to describe require no more than a combination of Newton's laws of mechanics and Maxwell's electromagnetic theory. At either end of this scale lie the two extreme worlds of the very small, describbed by quantum mechanics, and the very large, described by general relativity." [p. 193]
"... quantum mechanics, as proposed by Heisenberg and Schrodinger, was not consistent with special relativity." [p. 192]
These equations were subsequently modified "but the new equation had a rather serious problem: the quantum probabilities it predicted from its wavefunction could be negative!" [p. 193]
"In 1928, Paul Dirac ... proposed an alternative equation to Schrodinger's which was not only 'fully relativistic' but also took into account the electron's spin ... It was this equation that led Dirac to the theoretical prediction of anti-particles and the idea of electron-positron creation and annihilation." [p. 194]
"... Dirac had also published the first pioneering paper combining quantum mechanics with Maxwell's theory of light to give the first quantum theory of the photon. What he did was 'quantize' the electromagnetic field." [p. 194]
"The basic idea of a quantum field theory is that something like an electric field can be thought of as many virtual photons popping in and out of existence all the time." [p. 194]
In 1949 Richard Feynman, Julian Schwinger and Sin-Itiro Tomonaga each independently finessed a way of handling the mathematical infinities in the equations and created a theory called quantum electrodynamics (QED).
"This theory of the nature of the interaction of light with matter is the most fundamental and important in the whole of science. All mechanical, electrical and chemical laws and phenomena are ultimately derived from it. Apart from the force of gravity, and the forces acting inside the atomic nucleus, all processes in nature are ultimately explained by QED." [p. 196]
The goal of the last half-century has been to see if it is possible to describe the other three forces using a quantum field theory.
"Physicists now realize that to unify the four forces of nature, they must find a way of combining general relativity with quantum field theory ... The problem is that these two theories have hardly anything in common apart from the fact that they both approximate to Newtonian physics on an everyday scale. They depart from this limit at the extremes of very small objects and distances (quantum mechanics) and very large objects and distances (general relativity). But with this departure they take on very different mathematical structures, making them incompatible." [p. 205]
"... space and time themselves must also be ultimately composed of irreducible lumps." [p. 207]

A great chapter!

I have also skim read the remaining two chapters, but do not feel it necessary to make notes on them.

The diagrams and color-images in this book are among the best I have ever seen in a science book. Undestanding is enhanced when it is a combination of mathematics, language and visual imagery. What is lacking is motion. This is where computers and modeling can make a contribution.

Perhaps the developments in projects such as Second Life will lead to tools that can be used to describe our understanding of ideas rather than being simply used to create simulated physical appearances. For example, color may be thought of as another dimension. This is already being used to great effect in software packages such as Mathematica. The author of this system, Stephen Wolfram, has proposed (A New Kind of Science) a radically different way of conceptualizing models using the idea of feedback and recursion. Roger Penrose, one of the leading theoretical physicists alive today, has also written a couple of very thought-provoking books (Shadows of the Mind, The Road to Reality) about the future of science. Googling the titles of these two books is almost as much fun as reading the original books.

Tags: physics, science, quantum

7:30 am

I have now completed reading the two books that have occupied most of my time during the last week. Now to give a few minutes thought to what I should read next. I need to identify both a fiction and a non-fiction book. For non-fiction, I am leaning toward mathematics. For fiction, I am looking for a change of pace. I have opted for "South of the Border, West of the Sun" by Haruki Murakami (1998). I thoroughly enjoyed reading his "Kafka on the Shore" and am looking forward to this. Looking at my mathematics books, I have picked "Symmetry" by Marcus du Sautoy.

At some point I should return to my calculus activities!