This introduction presents an overview of the key concepts discussed in the subsequent chapters of this book. The book explores the minimalist ontology of matter points and their dynamics in general philosophical as well as mathematical terms, independently of any particular physical theory. It shows how this ontology fits both classical mechanics of gravitation and quantum mechanics, as long as the latter includes a primitive ontology of matter distributed in ordinary space, as in Bohmian mechanics. The book points out the similarities between these two theories as well as their differences. It explains how in both cases one gets from an ontology and a dynamics defined for the universe as a whole to a description of subsystems of the universe and a dynamics for them. The book shows how an ontology of persisting particles that move according to a deterministic law can explain the characteristic phenomena of quantum field theory and ground its empirical predictions.
This introduction presents an overview of the key concepts discussed in the subsequent chapters of this book. The book explores the minimalist ontology of matter points and their dynamics in general philosophical as well as mathematical terms, independently of any particular physical theory. It shows how this ontology fits both classical mechanics of gravitation and quantum mechanics, as long as the latter includes a primitive ontology of matter distributed in ordinary space, as in Bohmian mechanics. The book points out the similarities between these two theories as well as their differences. It explains how in both cases one gets from an ontology and a dynamics defined for the universe as a whole to a description of subsystems of the universe and a dynamics for them. The book shows how an ontology of persisting particles that move according to a deterministic law can explain the characteristic phenomena of quantum field theory and ground its empirical predictions.
This introduction presents an overview of the key concepts discussed in the subsequent chapters of this book. The book explains the historical development of Bohmian mechanics, Bohmian mechanics for single particle and for many particle systems. It discusses the dynamics of a single hydrogen atom interacting with a strong laser and presents a clear example on how a Bohmianthinking on superluminal velocities and nonlocal interactions helps in extending the quantum theory towards relativity and quantum field theory. The book also explains model nanoscale electron devices and their Bohmiancomputing development for knowing the ab initio quantum mechanical structure, energetics and thermodynamics of multiatoms systems. It deals with new cosmological models describing the accelerating universe in the spatially flat case. The book describes how many conceptual problems that appear in a description of gravity in quantum mechanical terms, such as the measurement problem and the problem of time, can be overcome by adopting a Bohmian perspective.
The Super-Humean strategy is a purely philosophical one: in a nutshell, on this strategy, there is a relationalist ontology, but a non-relationalist physical theory. When it comes to quantum mechanics, a discussion of ontology makes sense only if one spells out to which version of the quantum mechanics one is committed—that is, how one solves the measurement problem. The quantum theory going back to de Broglie and D. Bohm is the most prominent of them. It is based on a primitive ontology of permanent point particles as in the classical mechanics. The dynamical structure that a physical theory introduces is in any case defined for the universe as a whole. For instance, as soon as there are dynamical parameters whose value is conserved throughout the universe—such as the total energy—there are global correlations in the motions of the matter points.
Abstract The book starts with a description of classical mechanics then discusses the quantum phenomena that require us to give up our commonsense classical intuitions. We consider the physical and conceptual arguments that led to the standard von Neumann-Dirac formulation of quantum mechanics and how the standard theory explains quantum phenomena. This includes a discussion of how the theory’s two dynamical laws work with the standard interpretation of states to explain determinate measurement records, quantum statistics, interference effects, entanglement, decoherence, and quantum nonlocality. A careful understanding of how the standard theory works ultimately leads to the quantum measurement problem. We consider how the measurement problem threatens the logical consistency of the standard theory then turn to a discussion of the main proposals for resolving it. This includes collapse formulations of quantum mechanics like Wigner’s extension of the standard theory and the GRW approach and no-collapse formulations like pure wave mechanics, the various many-worlds theories, and Bohmian mechanics. In discussing alternative formulations of quantum mechanics we pay particular attention to the explanatory role played by each theory’s empirical ontology and associated metaphysical commitments and the conceptual trade-offs between theoretical options.
In this introductory chapter, which actually is the core of the entire book, we make a serious effort to bring together a variety of ideas from philosophy and physics. We first lay the epistemological foundations for our approach to particle physics. These philosophical foundations, combined with tools borrowed from the amazingly sophisticated, but still not entirely satisfactory, mathematical apparatus of present-day quantum field theory and augmented by some new ideas, are then employed to develop a mathematical representation of fundamental particles and their interactions. In this process, also the relation between “fundamental particle physics” and “quantum field theory” is going to be clarified. This first chapter consists of two voluminous sections: a number of philosophical contemplations followed by a discussion of mathematical and physical elements . The reader might wonder why these massive sections are not presented as two separate chapters. The reason for keeping them together is the desire to emphasize the intimate relation between these two sections: the selection and construction of the mathematical and physical elements is directly based on our philosophical contemplations. The beauty of the entire approach is a fruit of this intimate relationship. The presentation of the material in this chapter is based on the assumption that the reader has a basic working knowledge of linear algebra and quantum mechanics. If that is not the case, the reader might want to consult the equally entertaining and serious introduction Quantum Mechanics: The Theoretical Minimum by Susskind and Friedman [4]. The book Quantum Mechanics and Experience by Albert [5] offers a fascinating introduction with a strong focus on the measurement problem. An almost equation-free discussion of the history and foundations of quantum mechanics can be found in the book Einstein, Bohr and the Quantum Dilemma: From Quantum Theory to Quantum Information by Whitaker [6]. Complex vector spaces, Hilbert space vectors and density matrices for describing states of quantum systems, bosons and fermions, canonical commutation relations, Heisenberg's uncertainty relation, the Schrodinger and Heisenberg pictures for the time evolution of quantum systems, as well as a basic idea of the measurement process are all referred or alluded to in Section 1.1; these basics of quantum mechanics are recapped only very briefly in Section 1.2. The crucial construct of Fock spaces is explained in a loose way in Section 1.1.3 and later elaborated in full detail in Section 1.2.1.
This introduction presents an overview of the key concepts discussed in the subsequent chapters of this book. The book reviews classical physical and quantum theories for nonspecialists, building on the basics to introduce recent advances. A definition of physical is included for specialists also to consider. The book analyzes quantum theory interpretations, revealing a developmental progression from the standard, many-worlds, decoherence/consistent histories, quantum probability, quantum information field, and transactional interpretations to neorealism. It outlines a new holistic interpretation of quantum theory; of major significance is the subtle concept of levels of spacetime. The book considers loop quantum gravity, string, inflationary big bang, and unified field theories. The diverse interpretations are in large part due to focusing on the observed as the only reality: the process of observing and the observer were practically ignored.
In general, a physical theory is based on some fundamental principles concerning space, time, matter, and the laws prescribing how matter is distributed in space and how it evolves in time, and even how spacetime itself changes in response to the changes of matter. The spectrum of the known theories is very diverse, since they are based on different assumptions. Some theories assume that space and time are totally independent, some that they are warped in a continuum named "spacetime", and some even that there are more dimensions than the usual 3+1. Most theories consider that space and time are continuous, but many recent theories consider them to be discrete. Most dynamical laws of fundamental Physics are deterministic, but apparently Quantum Mechanics shows that they may have an indeterministic component. Despite these distinctions between various theories, our intuition and experience tells us that they have a lot in common. In this paper I will try to capture the common features in a single mathematical structure. This is not a Theory of Everything, but only a mathematical structure which is common to most physical theories known so far. We will see that these theories can be obtained as particular cases of this structure, which I will call "world". In particular, the worlds described by the Classical Mechanics, the Theory of Relativity and the Quantum Mechanics are examples of worlds according to this definition, but also some theories attempting to unify gravity and QM, like String Theory. The purpose of this distillation is to provide a mathematical common background to both physical and metaphysical discussions about the various theories of the World.