891 research outputs found

    Quantum Mechanics as Classical Physics

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    Here I explore a novel no-collapse interpretation of quantum mechanics which combines aspects of two familiar and well-developed alternatives, Bohmian mechanics and the many-worlds interpretation. Despite reproducing the empirical predictions of quantum mechanics, the theory looks surprisingly classical. All there is at the fundamental level are particles interacting via Newtonian forces. There is no wave function. However, there are many worlds.Comment: 25 page

    Forces on Fields

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    In electromagnetism, as in Newton's mechanics, action is always equal to reaction. The force from the electromagnetic field on matter is balanced by an equal and opposite force from matter on the field. We generally speak only of forces exerted by the field, not forces exerted upon the field. But, we should not be hesitant to speak of forces acting on the field. The electromagnetic field closely resembles a relativistic fluid and responds to forces in the same way. Analyzing this analogy sheds light on the inertial role played by the field's mass, the status of Maxwell's stress tensor, and the nature of the electromagnetic field.Comment: 26 pages, 2 figure

    The Mass of the Gravitational Field

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    By mass-energy equivalence, the gravitational field has a relativistic mass density proportional to its energy density. I seek to better understand this mass of the gravitational field by asking whether it plays three traditional roles of mass: the role in conservation of mass, the inertial role, and the role as source for gravitation. The difficult case of general relativity is compared to the more straightforward cases of Newtonian gravity and electromagnetism by way of gravitoelectromagnetism, an intermediate theory of gravity that resembles electromagnetism.Comment: 39 pages, 1 figur

    Killer Collapse: Empirically Probing the Philosophically Unsatisfactory Region of GRW

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    GRW theory offers precise laws for the collapse of the wave function. These collapses are characterized by two new constants, λ and σ. Recent work has put experimental upper bounds on the collapse rate, λ. Lower bounds on λ have been more controversial since GRW begins to take on a many-worlds character for small values of λ. Here I examine GRW in this odd region of parameter space where collapse events act as natural disasters that destroy branches of the wave function along with their occupants. Our continued survival provides evidence that we don't live in a universe like that. I offer a quantitative analysis of how such evidence can be used to assess versions of GRW with small collapse rates in an effort to move towards more principled and experimentally-informed lower bounds for λ

    Marine flora and fauna of the Eastern United States Anthozoa: Acitniaria, Corallimorpharia, Ceriantharia, and Zoanthidea

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    This key includes 60 species of sea anemones and their relatives in the orders Actiniaria, Corallimorpharia, Ceriantharia, and Zoanthidea. Species from the intertidal zone, continental slope, and deep sea are included over a geographic range from Atlantic Canada to approximately South Carolina. In addition to the illustrated key itself, characteristics of each species are summarized in tabular form, including morphology, distribution, and types and sizes of cnidae. Ecological and taxonomic information on each species are also included in an annotated species list. (PDF file contains 76 pages.
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