The Dancing Wu Li Masters (28 page)

According to quantum mechanics, a subatomic particle is not a particle like a particle of dust. Rather, subatomic particles are “tendencies to exist’ and “correlations between macroscopic observables”. They have no objective existence. That means that we cannot assume, if we are to use quantum theory, that particles have an existence apart from their interactions with a measuring device. As Heisenberg wrote:

In the light of the quantum theory…elementary particles are no longer real in the same sense as objects of daily life, trees or stones…
3

When an electron, for example, passes through a photographic plate it leaves a visible “track” behind it. This “track,” under close examination, is actually a series of dots. Each dot is a grain of silver formed by the electron’s interaction with atoms in the photographic plate. When we look at the track under a microscope, it looks something like this.

Ordinarily we would assume that one and the same electron, like a little baseball, went streaking through the photographic plate and left this trail of silver grains behind it. This is a mistake. Quantum mechanics tells us the same thing that Tantric Buddhists have been saying for a millennium.
The connection between the dots (the “moving
object”) is a product of our minds
and it is not really there. In rigorous quantum mechanical terms, the moving object—the particle with an independent existence—is an unprovable assumption.

“According to our customary way of reasoning,” wrote David Bohm, a professor of physics at Birkbeck College, University of London,

we could suppose that the track of grains of silver indicates that a real electron moves continuously through space in a path somewhere near these grains, and by interaction caused the formation of the grains. But according to the usual interpretation of the quantum theory, it would be incorrect to suppose that this really happened. All that we can say is that certain grains appeared, but we must not try to imagine that these grains were produced by a real object moving through space in the way in which we usually think of objects moving through space. For although this idea of a continuously moving object is good enough for an approximate theory, we would discover that it would break down in a very exact theory.
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The natural assumption that objects, like “particles,” are real things that run their course in space and time according to causal laws regardless of whether we are around to observe them or not is repudiated by quantum mechanics. This is especially significant because quantum mechanics is
the theory
of physics. It has explained successfully everything from subatomic particles to stellar phenomena. There never has been a more successful theory. It has no competition.

Therefore, when we look at the tracks in a bubble chamber, we are left with the question, “What made them?” The best answer that physicists have so far is that “particles” are actually interactions between fields. A field, like a wave, is spread out over a much larger area than a particle (a particle is restricted to one point). A field, moreover, completely fills a given space, like the gravitational field of the earth fills all of the space immediately around it.

When two fields interact with each other they interact neither gradually nor at all their areas of contact. Rather, when two fields
interact, they do it
instantaneously
and at one single point in space (“instantaneously and locally”). These instantaneous and local interactions make what we call particles. In fact, according to this theory, these instantaneous and local interactions
are
“particles.” The continual creation and annihilation of particles at the subatomic level is the result of the continual interaction of different fields.

This theory is called quantum field theory. Some major cornerstones of the theory were laid in 1928 by the English physicist Paul Dirac. Quantum field theory has been highly successful in predicting new types of particles and in explaining existing particles in terms of field interactions. According to this theory, a separate field is associated with each type of particle. Since only three types of particles were known in 1928, only three different fields were required to explain them. The problem today, however, is that there are over one hundred known particles, which, according to quantum field theory, require over one hundred different fields. This abundance of theoretical fields is somewhat awkward, not to mention embarrassing, to physicists whose goal is to simplify nature. Therefore, most physicists have given up the idea of a separate field existing for each type of particle.

Nevertheless, quantum field theory is still an important theory not only because it works, but also because it was the first theory to merge quantum mechanics and relativity, albeit in a limited way. All physical theories, including quantum theory, must satisfy the requirement of relativity theory that the laws of physics be independent of the state of motion of the observer. Attempts to integrate the theory of relativity with quantum theory, however, have been generally unsuccessful. Nonetheless, both relativity and quantum theory are required, and routinely used, in the understanding of particle physics. Their forced relationship is best described as strained but necessary. In this regard, one of the most successful integrations of the two is quantum field theory, although it covers only a relatively small range of phenomena.
*

Quantum field theory is an
ad hoc
theory. That means that, like Bohr’s famous specific-orbits-only model of the atom, quantum field theory is a practical but conceptually inconsistent scheme. Some parts of it don’t fit together mathematically. It is a working model designed around the available data to give physicists a place to stand in the exploration of subatomic phenomena. The reason that it has been around so long is that it works so well. (Some physicists think that it may work
too
well. They fear that the pragmatic success of quantum field theory impedes the development of a consistent theory.)

Even with these well-known shortcomings, the fact is that quantum field theory is a successful physical theory, and it is premised on the assumption that
physical reality is essentially nonsubstantial
. According to quantum field theory, fields alone are real.
They
are the substance of the universe and not “matter.” Matter (particles) is simply the momentary manifestations of interacting fields which, intangible and insubstantial as they are, are the only real things in the universe. Their interactions seem particle-like because fields interact very abruptly and in very minute regions of space.

“Quantum field theory” is, of course, an outrageous contradiction in terms. A quantum is an indivisible whole. It is a small piece of something, while a field is a whole area of something. A “quantum field” is the juxtaposition of two irreconcilable concepts. In other words, it is a paradox. It defies our categorical imperative that something be either
this
or
that
, but not both.

The major contribution of quantum mechanics to western thought, and there are many, may be its impact on the artificial categories by which we structure our perceptions, since ossified structures of perception are the prisons in which we unknowingly become prisoners. Quantum theory boldly states that something can be this
and
that (a wave
and
a particle).
*
It makes no sense to ask which of these
is really the true description. Both of them are required for a complete understanding.

In 1922, Werner Heisenberg, as a student, asked his professor and friend-to-be, Niels Bohr, “If the inner structure of the atom is as closed to descriptive accounts as you say, if we really lack a language for dealing with it, how can we ever hope to understand atoms?”

Bohr hesitated for a moment and then said, “I think we may yet be able to do so. But in the process we may have to learn what the word ‘understanding’ really means.”
5

In human terms, it means that the same person can be good
and
evil, bold
and
timid, a lion
and
a lamb.

 

All of the above notwithstanding, particle physicists of necessity analyze subatomic particles as if they
were
like little baseballs that fly through space and collide with each other. When a particle physicist studies a track on a bubble-chamber photograph of a particle interaction, he assumes that it
was
made by a little moving object, and that the other tracks on the photograph likewise were made by small moving objects. In fact, particle interactions are analyzed in much the same terms that can be applied to the collision of billiard balls. Some particles collide (and are annihilated in the process) and other newly created particles come flying out of the collision area. In short, particle interactions are analyzed essentially in terms of masses, velocities, and momenta. These are the concepts of Newtonian physics and they also apply to automobiles and streetcars.

Physicists do this because they have to use these concepts if they are to communicate at all. What is available to them is usually a black photograph with white lines on it. They know that (1) according to quantum theory, subatomic particles have no independent existence of their own, (2) subatomic particles have wave-like characteristics as
well as particle-like characteristics, and (3) subatomic particles actually may be manifestations of interacting fields. Nonetheless, these white lines (more patterns) lend themselves to analysis in classical terms, and so that is how particle physicists analyze them.

This dilemma, the dilemma of having to talk in classical terms about phenomena which cannot be described in classical concepts is the basic paradox of quantum mechanics. It pervades every part of it. It is like trying to explain an LSD experience. We try to use familiar concepts as points of departure, but beyond that, the familiar concepts do not fit the phenomena. The alternative is to say nothing at all.

“Physicists who deal with the quantum theory,” wrote Heisenberg,

are also compelled to use a language taken from ordinary life. We act as if there really were such a thing as an electric current [or a particle] because, if we forbade all physicists to speak of electric current [or particles] they could no longer express their thoughts.
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Therefore, physicists talk about subatomic particles as if they were real little objects that leave tracks in bubble chambers and have an independent (“objective”) existence. This convention has been extremely productive. Over the last forty years almost one hundred particles have been discovered. They constitute what Kenneth Ford calls the particle zoo.
*

 

The first thing to know about the particle zoo is that every particle of the same species looks exactly alike. Every electron looks exactly like every other electron. If you’ve seen one, you’ve seen them all. Likewise, every proton looks exactly like every other proton, every neutron looks exactly like every other neutron, and so on. Subatomic particles of the same type are absolutely indistinguishable.

Subatomic particles of different types, however, can be recognized by their distinguishing characteristics (properties). The first distinguishing characteristic of a subatomic particle is its mass. A proton, for example, has about 1800 times more mass than an electron. (This does not necessarily mean that a proton is 1800 times larger than an electron since mass and size are not the same thing—a pound of lead and a pound of feathers have the same mass).

When physicists refer to the mass of a particle, unless they indicate otherwise, they are referring to the mass of the particle when it is at rest. The mass of a particle at rest is called its rest mass. Any mass other than a rest mass is called a relativistic mass. Since the mass of a particle increases with velocity, a particle can have any number of relativistic masses. The size of a particle’s relativistic mass depends upon its velocity. For example, at 99 percent of the speed of light a particle’s mass is seven times larger than it is when the particle is at rest.

At velocities above 99 percent of the speed of light particle masses increase dramatically. When the former electron accelerator at Cambridge, Massachusetts, was in operation, it received electrons from a small feeder accelerator. The electrons from the feeder accelerator were fed into the main accelerator at .99986 the velocity of light. The main accelerator then increased the velocity of these electrons to .999999996 the speed of light. This increase in velocity may look significant, but actually it is negligible. The difference between the initial velocity of the accelerated electrons and the final velocity of the accelerated electrons is the same as the difference in velocity between one automobile that can make a given trip in two hours and a faster automobile that can make the same trip in one hour fifty-nine minutes and fifty-nine seconds.
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The
mass
of each electron, however, increased from 60 times to as much as 11,800 times the electron rest mass! In other words, particle accelerators are misnamed. They do not increase the velocities of subatomic particles (the definition of “acceleration”) as much as they increase their mass. Particle accelerators are actually particle enlargers (massifiers?).

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