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Author: Rodney A. Brooks
Quotes of Author: Rodney A. Brooks

Rodney A. Brooks _ Fields of Color: The theory
general spin is an abstract mathematical concept that is related to the number of field components and how they change when viewed from different angles. The more field components, the higher the
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Rodney A. Brooks _ Fields of Color: The theory
QFT deals with the structure and operation of the cosmos in the here-and-now, and not the whys and wherefores.
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Rodney A. Brooks _ Fields of Color: The theory
It is clear the field collapse and renormalization have something in common: they both arise because something happens at the single quantum level that is not described by QFT. Renormalization is necessary because QFT is not able to explain the way in which a field quantum interacts with its self-field. Field collapse is a mystery because QFT doesn't predict when or how a quantum will change its state or be absorbed. If one of these gaps should ever be filled, I believe that the other one may be also.
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Rodney A. Brooks _ Fields of Color: The theory
The job of science is to look beyond our intuition, to find out by any means possible what's really going on, and to give up old ways of thinking when the evidence requires it.
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Rodney A. Brooks _ Fields of Color: The theory
Non-locality. One of the most troubling aspects of field collapse is that it is instantaneous and occurs at the same time at widely separated points. Physicists call this non-locality. This is especially bothersome when the sudden change involves two entangled field quanta. Einstein argued vehemently against the idea of non-locality, claiming that it violated a result of his Principle of Relativity - that nothing can be transmitted faster than the speed of light. Now Einstein's postulate {which we must remember was only a guess} is indeed valid in relation to the evolution and propagation of fields as described by the field equations. However field collapse is not described by the field equations, so there is no reason to expect or to insist that it falls in the domain of Einstein's postulate. Non-locality is a fact; it has been experimentally documented. Nor does it lead to any paradoxes or inconsistencies. Even those who believe in particles as the ultimate reality acknowledge that something happens non-locally. Just as we said, "So the earth is round, not flat; that's surprising but I can live with it", so we can say, "Fields suddenly collapse. It's not what I expected but I can live with it." There are no logical contradictions involved.
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Rodney A. Brooks _ Fields of Color: The theory
I hope that, like Schwinger, Weinberg, Wilczek, Hobson {and me}, you will choose a reality made of quantum fields - properties of space that are described by the equations of QFT. This is a picture that resolves all three of Einstein's enigmas {see Appendices}, a picture that solves the action-at-a-distance problem that even Newton found unacceptable, a picture based on simple and elegant equations {take my word for that}, a picture that explains or is consistent with all the data known to date. And on top of that, QFT provides the most philosophically acceptable picture of nature that I can imagine."
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Rodney A. Brooks _ Fields of Color: The theory
My mission soon turned into a labor of love, with emphasis on labor. I had not anticipated the breadth and depth of the subject, or the drama as our greatest minds waged what I think is our greatest battle: to understand the world we find ourselves in {a far more worthy battle than the wars we are so good at waging against each other}. By drama I mean not only the philosophic struggle to wrest nature's secrets from their most hidden recesses with only the flimsiest of evidence; I also mean the human side of the story - stories that are sometimes tragic, sometimes nettlesome, but always fascinating.
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Rodney A. Brooks _ Fields of Color: The theory
The helium nucleus, for example, contains two protons and two neutrons. If the neutrons were not there, the electrical repulsion between the protons would overcome the strong binding force. However if two neutrons are also present, the binding force is increased {because there are now four nucleons}, while the electrical repulsion between the protons is weakened because they are not as close together. The result is a stable helium nucleus-also known as an alpha particle {the same radiation used by Rutherford in his gold foil experiment}. If more protons are present, as in the heavier elements, more neutrons are needed to dilute the increasingly large repulsive force. This is why in most atoms the neutrons outnumber the protons. However if there are too many neutrons the nucleus will break down for a reason known as the Pauli Exclusion Principle {See Chap. 6}.
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Rodney A. Brooks _ Fields of Color: The theory
Force. Before fields were recognized, forces were thought {except by Newton} to happen through "action at a distance". That is, a body or particle in one place causes a body in another place to move, without any medium in between. When Faraday introduced the concept of fields, this picture was changed: The first body creates a field in the surrounding space and this field then exerts a force on the second body. In QFT, everything is fields, even the bodies; reality consists only of fields and interactions between fields. The effect of force comes from terms in the field equations that describe how one field influences another. Thus the force field does not exert a force on another "body" in the classical sense. Instead it interacts with the field that constitutes the other "body" and alters its evolution, causing its spatial distribution to change. This change in evolution is equivalent to the older classical picture of a particle experiencing a force. Indeed, Newton's laws of motion can be derived from the equations of QFT!
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Rodney A. Brooks _ Fields of Color: The theory
The vacuum field. Separate and attached fields are not the only fields that exist in QFT. Even in a region where they are absent, or essentially zero, there still is a background field known as the vacuum field.
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Rodney A. Brooks _ Fields of Color: The theory
Because quanta are fields, they do not have sharp edges and can spread over large distances, but no matter how spread out they are, each quantum maintains its own identity. If it is absorbed or changes its spin state, it does so as a unit. Because of this all-or-nothing behavior, quanta in many ways mimic the behavior of particles.
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Rodney A. Brooks _ Fields of Color: The theory
those events proceed, not in
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