Wilczek Book Impressions


The Lightness of Being; Mass, Ether and the Unification of Forces

by Frank Wilczek (Nobel Laureate in Physics), (Basic Books 2008).

I was attracted to this book by its title.

There is a mythology book I simply loved back in the 1980s. A book with a fascinating peppering of social evolution observations by the title The Time Falling Bodies Take to Light: Mythology, Sexuality & the Origin of Culture by William Irwin Thompson. (St. Martins 1981). Wilczek’s title seemed somewhat similar, grabbing my attention because of Thompson’s book.

Wilczek chose the title in part because it is a variation on one of his own favorite books: The Unbearable Lightness of Being by Milan Kundera.  He also chose the title because it fit the book’s content.

I loved Wilczek's book too, but perhaps not as much as I loved Thompson’s book. Perhaps? Yes, because I don’t know if I accurately remember how much I loved that book almost three decades ago.  I have it on my bookshelf, and will have to read it once more.

So why did I select another book on modern physics? Because I was very critical of another book on physics (click here if you really want to go there) and am always looking to see if my harsh criticisms are justified, given that physics is moving ahead at an amazing pace, and physicists are learning new things continually. I loved this book because it shared many new insights that were explained in a way that I could understand. Amazing!

So, what were the highlights of this book, for me?

Pages 32-34 caught my attention because they discuss some elementary particles, how they were first predicted from theory and then observed in experiments. There was none of this phony discussion of the observer’s mind, the observer’s expectations, influencing the outcome of experiments to create the particles that were expected.   This was one of the claims I attacked in the above-noted and linked critical review.

Page 102 mentions two more subatomic entities predicted and then observed. But its point is that although we are getting to know the particles and the forces of subatomic, quantum physics, the problem of quantum gravity is still unsolved. This is the topic of several books on superstring theory I read last year, and given how difficult the concepts of superstring theory were for me to understand, I was surprised and amused at these observations by Wilczek about superstring theory:

Superstring theory is a valiant attempt but very much a work in progress. At present it’s more a collection of hints about what a theory might look like rather than a concrete world-model with definite algorithms and predictions. And it hasn’t deeply incorporated the basic Grid ideas. (For experts: string field theory is clumsy at best.)

I really liked Wiczek’s explanation of the “Grid.” On page 76, he explains he might have selected the word “Matrix,” but . . . “the sequels tarnished that candidate.” On page 75 he illustrated “empty space” as being a multidimensional Grid containing dark energy, condensates, a metric field and a quantum field.

So where does ordinary matter come from, the stuff we are made of? Wilczek says that

Ordinary matter is a secondary manifestation of the Grid, tracing its level of excitation.

I was hoping that he would mention that in order to have matter arise from a vacuum requires serious excitation, since this is a point I drove home in my very critical review. The origin of mass, as we experience it, is the primary subject of the book, and the explanation is one of the more fascinating things I have read in a very long time. I understood it when I read it, but would have to read it again, several times, to explain it.

But maybe I was too mean about the need to prod the vacuum with serious energy intrusions to get anything resembling matter to arise from it. I suggested the only place we see spontaneous formation of matter now is in our power-tools for physicists and at the high-energy boundary of a black hole. But perhaps this is missing the point that the energy required for making the vacuum interact with real particles, through forming virtual particles in reaction, is not all that high. It goes on all the time, but we don't observe it except in our high-energy experiments or at the edge of black holes. Shooting an electrically- or ‘color’-charged particle into the vacuum stimulates formation of short lived virtual particles that effectively shield the intruding particle, thus reducing the spatial persistence of energy fields associated with the particle, and this has implications for why we see things, and do not see things, in the cosmos.

I found it fascinating that Wilczek drew insights from earlier physicists about new and very modern notions. Page 105 gives an example, using Newton from 1692, and Einstein from 1917, to show they realized that the vacuum of space must play a role in distributing matter in the universe, hence it must have properties, including a dark energy and a non-zero density.

On pages 117 and 118, Wilczek explains Einstein’s “spooky action-at-a-distance.” This is a favorite cited by the ‘new age’ -branch of physics- <my joke>, and one I mercilessly attacked in my mean review. Wilczek dismisses the mystery the same way I did, by saying it’s a simple effect reflecting quantum mechanics dictating that two particles (“qubits” in Wilczek’s parlance) close together will have opposite spin orientations, and when you separate them, no matter how far, conservation of momentum has their spin orientations remain the same. This effect, says Wilczek,

. . . “would annoy Einstein, Podolsky, and Rosen, because they exhibit the essence of the famous EPR paradox. Measuring the spin of the first qubit tells you about the result you’ll get by measuring the second bit, even though they might be physically separated by a large distance. On the face of it, this “spooky action-at-a-distance,” to use Einstein’s phrase, seems capable of transmitting information (telling the second spin which way it must point) faster than the speed of light. But that’s an illusion, because to get two qubits into a definite state we had to start with them close together. Later we can take them far apart, but if the qubits can’t travel faster than the speed of light, neither can any message they carry with them.”

The context for this aside is a (more important) explanation of why the model for understanding quantum reality has 32 dimensions!  Pages 119-120 explain:

The quantum Grid, which embodies our deepest understanding of reality, requires many qubits at each point in space and time. The qubits at a point describe the various things that might be happening at that point. For example, one of them describes the probability that (if you look) you will observe an electron with spin up or down, another the probability that (if you look) you will observe an electron with spin up or down, another the probability that (if you look) you will observe an antielectron with spin up or down, another the probability that (if you look) you will observe a red u quark with spin up or down. . . . Others describe possible results if you look for photons, gluons, or other particles. On top of that, if space and time are continuous–as the existing laws of physics, so far very successfully, assume–then the number of space-time points is highly infinite

Pages 120-121 add:

. . . We’ve talked before about the spontaneous activity of the Grid. It’s full of quantum fluctuations, or virtual particles. Those are rough, informal descriptions of a reality we now have the language to express more precisely. To say that the Grid contains spontaneous activity is to say that its state is not a simple one. If we look with high resolution in space and time we see what’s going on in the entity we call empty space . . ., we find many possible results. Each time we look we see something different. Each observation uncovers a piece of the wave function that describes a typical, very small region of space. Each observation embodies a possibility that occurs, multiplied by some probability amplitude, within that wave function.

. . . There are (at least) two fundamental reasons why it can be very difficult to predict the future, even if we have all the right equations. One is chaos theory. Roughly speaking, chaos theory says that small uncertainties in your knowledge of the state of the world at time t0 introduce very large uncertainties in what you can deduce about the state of the world at a significantly later time t1.

The other is quantum theory. As we’ve discussed, quantum theory generally predicts probabilities, not uncertainties. Actually, quantum theory gives you perfectly definite equations for how the wave function of a system changes with time. But when you use the wave function to predict what you’ll observe, what it gives you is a set of probabilities for different outcomes.

The last two paragrpahs seem as applicable to real-world predictions over long times and spaces as they are applicable to subatomic physics.  A related observation is made on page 123:

Once we’ve got “empty” space humming, we can pluck it. That is, we can disturb Grid by injecting some extra activity and letting things settle down. If we find stable, localized concentrations of energy, we’ve found–that is, computed–stable particles. We can match them, (if the theory’s right!) To protons p, neutrons n, and the rest. If we find localized concentrations of energy that persist for a good while before dissipating, we’ve found unstable particles. They should match the p meson, the baryon, and their kin.

All of this interesting discussion is in the context of what can be calculated, and observed in experiments, and how much progress and knowledge that represents. Page 127 concludes:

Through difficult calculations of merciless precision that call upon the full power of modern computer technology, they’ve shown that unbendable equations of high symmetry account convincingly and in quantitative detail for the existence of protons and neutrons, and for their properties. They’ve demonstrated the origin of the proton’s mass, and thereby the lioness’s share of our mass. I believe this is one of the greatest scientific achievements of all time.

Chapter 10 covers pages 128 through 132 is all, but it is an important chapter for me because it explains that doing calculations isn’t enough, one also needs to obtain understanding and that is accomplished through simpler abstractions, models that can be shown to have limited applicability but support insight, and thus translate into understanding and knowledge.

Pages 129-130 mention that the great breakthrough mentioned in the previous chapter, about the mass of protons and neutrons, require them to be made of nearly massless quarks and gluons.

The equations of QCD [Quantum Chromo-Dynamics] output Mass Without Mass. It sounds suspiciously like something for nothing. How did it happen?

Fortunately, it is possible to get a rough, professor-like understanding of that apparent miracle. We just have to put together three ideas we’ve already discussed separately.

Wilczek then discusses these three ideas and wraps them into an explanation. I am not going to repeat it here, read the book, but I will paraphrase his last lines on page 132 as saying in essence: that your weight [how mass is measured on Earth] is your energy content. Makes me feel powerful, since I am overweight!

On page 134 Wilczek reaches into the realm of ancient science and modern mysticism to comment on the “Music of the Spheres.” He basically suggests that we are plucking the instrument that makes that music, so-called empty space, by injecting particles and watching space react, measuring the energies, which indicates the mass, of resulting particles:

“The masses of particles sound the Music of the Grid.”

Pages 152 and 153 at the start of Chapter 16, have Wilczek recapitulating the dynamics that lead to a mass for a proton. It is still complicated, but this time it is laid out in even plainer plain language, with a joke at the end about “The Revenge of the Grid” as a sci-fi theme. I was originally going to cite that language here because it is the heart of the book for me, but I don’t want to discourage you from getting the book and reading for yourself.

Pages 156 and 157 were very interesting in their discussion of fundamental constants and relationships and how they . . . “are the enablers of profound principles of physics that couldn’t make sense without them.”

Page 179 wraps up a discussion of symmetry with an explanation of why things do not look as they should in experiments that “actively transfer large amounts of momentum and energy to the object being probed.” Wilczek is discussing high-energy accelerators (page 180) and the necessity of correcting for distortions of what we expect to see by the effects of the dynamics of the Grid. Referring to the solid basis of what is known about subatomic particles, embedded in the Standard Model, as the Core, Wilczek observes:

A great lesson from the Core is that the entity we perceive as empty space is in reality a dynamic medium full of structure and activity. The Grid, as we’ve called it, affects the properties of everything within it–that is, everything. We see things not as they are, but as through a glass, darkly. In particular, the Grid is aboil with virtual particles, and these can screen or antiscreen a source. That phenomenon, for the strong force, was central to the stories that unfolded in Parts I and II. [of this book] It occurs for the other forces too.

Continuing, Wilczek makes reference to the aforementioned coupling constants, fundamental constants that physics relies on:

So the coupling values we see depend on how we look. If we look crudely, we will not discern the basic sources themselves, but will see their images as distorted by the Grid. We will, in other words, see the basic sources mixed together with the cloud of virtual particles that surround them, unresolved. To judge whether perfect symmetry and unity of the forces occurs, we should correct for the distortions.

Unity of forces has previously been referred to as the Holy Grail of physics. On pages 180-181 Wilczek shows how much closer the forces correlate after distortions are corrected for. But it is still not close enough to allow a claim of unification to be made.

What gets us very close to unification is supersymmetry (SUSY) with its added dimensions. Wilczek --and I got a chuckle out of this-- cautions against New Age and sci-fi love for SUSY:

Before you get carried away with visions of spirit worlds and wormholes through hyperspace, let me hasten to add that the new dimensions have a very different character from the different dimensions of space and time. They are quantum dimensions.

On the next page Wilczek explains that these new dimensions as additional (“new”) layers of the grid. In these layers spin and mass may change but charges stay the same. With these insights factored in, all forces can be unified except gravity. On page 191 Wilczek proclaims that . . . “gravity fits too! (Roughly)”. Promises for further knowledge from the most recent additions to the power-tool kits available to physicists are foreshadowed in the last chapter, 21.

Wilczek discusses cosmology in several places and nicely explains dark matter as invisible matter, neither absorbing nor reflecting light.  He does not explain the nature of dark energy but discusses its necessity to modern physics on numerous pages (see the index).

What got my attention was page 105, where Einstein’s cosmological constant is equated with dark matter. Interesting.

Cosmological insights are invoked repeatedly, but I was hoping Wilczek would address the idea of other universes with different fundamental physical properties. He hinted somewhere early in the book that this was not likely, I believe, but I can’t find it back. I may actually have imagined it, after all the science fiction book I read just before reading Wilczek, called Otherness by David Brin (Bantam 1994), on its page 333 suggested that since black holes are where one universe spins off another, parallel universe, the seeds for new universes lie in older universes and the birth canal for the disturbance that produces new universes passes on the physical properties of the birthing universe as if it is vegetative propagation. I liked this logic, and it didn’t hurt that the fictional book's author is an astrophysicist.

Wilczek’s book is wonderfully insightful and amazingly understandable. What more could one ask for? To ask for more requires unheard of dimensions of reasonableness.

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