The Experts below are selected from a list of 75402 Experts worldwide ranked by ideXlab platform
Nicolas Gisin - One of the best experts on this subject based on the ideXlab platform.
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Indeterminism in Physics, Classical Chaos and Bohmian Mechanics: Are Real Numbers Really Real?
Erkenntnis, 2019Co-Authors: Nicolas GisinAbstract:It is usual to identify initial conditions of Classical dynamical systems with mathematical real numbers. However, almost all real numbers contain an infinite amount of information. I argue that a finite volume of space can’t contain more than a finite amount of information, hence that the mathematical real numbers are not physically relevant. Moreover, a better terminology for the so-called real numbers is “random numbers”, as their series of bits are truly random. I propose an alternative Classical Mechanics, which is empirically equivalent to Classical Mechanics, but uses only finite-information numbers. This alternative Classical Mechanics is non-deterministic, despite the use of deterministic equations, in a way similar to quantum theory. Interestingly, both alternative Classical Mechanics and quantum theories can be supplemented by additional variables in such a way that the supplemented theory is deterministic. Most physicists straightforwardly supplement Classical theory with real numbers to which they attribute physical existence, while most physicists reject Bohmian Mechanics as supplemented quantum theory, arguing that Bohmian positions have no physical reality.
Toshinori Suzuki - One of the best experts on this subject based on the ideXlab platform.
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initial phase shifts in the quantum beat resulting from the ultrafast internal conversion of pyrazine
Ultrafast Phenomena XIX, 2015Co-Authors: Yoshiichi Suzuki, Toshinori SuzukiAbstract:We present a simple interpretation of the phase-shifted quantum beat resulting from the nonradiative transition from higher to lower electronic states of pyrazine, based on Classical Mechanics and harmonic potentials.
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initial phase in quantum beat created via ultrafast internal conversion of pyrazine
19th International Conference on Ultrafast Phenomena (2014) paper 07.Mon.P1.26, 2014Co-Authors: Yoshiichi Suzuki, Toshinori SuzukiAbstract:We present a simple interpretation for the phase-shifted quantum beat that is created on the lower electronic state from the higher state upon a nonradiative transition, using the Classical Mechanics and harmonic potentials.
De Ronde Christian - One of the best experts on this subject based on the ideXlab platform.
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The (Quantum) Measurement Problem in Classical Mechanics
2020Co-Authors: De Ronde ChristianAbstract:In this work we analyze the deep link between the 20th Century positivist re-foundation of physics and the famous measurement problem of quantum Mechanics. We attempt to show why this is not an “obvious” nor “self evident” problem for the theory of quanta, but rather a direct consequence of the empirical-positivist understanding of physical theories when applied to the orthodox quantum formalism. In contraposition, we discuss a representational realist account of both physical ‘theories’ and ‘measurement’ which goes back to the works of Einstein, Heisenberg and Pauli. After presenting a critical analysis of Bohr’s definitions of ‘measurement’ we continue to discuss the way in which several contemporary approaches to QM —such as decoherence, modal interpretations and QBism— remain committed to Bohr’s general methodology. Finally, in order to expose the many inconsistencies present within the (empirical-positivist) presuppositions responsible for creating the quantum measurement problem, we show how through these same set of presuppositions it is easy to derive a completely analogous paradox for the case of Classical Mechanics
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The (Quantum) Measurement Problem in Classical Mechanics
2020Co-Authors: De Ronde ChristianAbstract:In this work we analyze the deep link between the 20th Century positivist re-foundation of physics and the famous measurement problem of quantum Mechanics. We attempt to show why this is not an "obvious" nor "self evident" problem for the theory of quanta, but rather a direct consequence of the empirical-positivist understanding of physical theories when applied to the orthodox quantum formalism. In contraposition, we discuss a representational realist account of both physical 'theories' and 'measurement' which goes back to the works of Einstein, Heisenberg and Pauli. After presenting a critical analysis of Bohr's definitions of 'measurement' we continue to discuss the way in which several contemporary approaches to QM --such as decoherence, modal interpretations and QBism-- remain committed to Bohr's general methodology. Finally, in order to expose the many inconsistencies present within the (empirical-positivist) presuppositions responsible for creating the quantum measurement problem, we show how through these same set of presuppositions it is easy to derive a completely analogous paradox for the case of Classical Mechanics.Comment: 24 page
Yassine Adam - One of the best experts on this subject based on the ideXlab platform.
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Open Systems in Classical Mechanics
2020Co-Authors: Baez, John C., Weisbart David, Yassine AdamAbstract:Span categories provide a framework for formalizing mathematical models of open systems in Classical Mechanics. The categories appearing in Classical Mechanics do not have pullbacks, which requires the use of generalized span categories. We introduce categories $\LagSy$ and $\HamSy$ that respectively provide a categorical framework for the Lagrangian and Hamiltonian descriptions of open Classical mechanical systems. The morphisms of $\LagSy$ and $\HamSy$ correspond to such open systems, and composition of morphisms models the construction of systems from subsystems. The Legendre transformation gives a functor from $\LagSy$ to $\HamSy$ that translates from the Lagrangian to the Hamiltonian perspective.Comment: 31 page
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Generalized Span Categories in Classical Mechanics and the Functoriality of the Legendre Transformation
eScholarship University of California, 2020Co-Authors: Yassine AdamAbstract:Span categories provide an abstract framework for formalizing mathematical models of certain physical systems. The categories appearing in Classical Mechanics do not have pullbacks, limiting the utility of span categories in describing such systems. We introduce the notion of a generalized span category and an augmentation of a generalized span category. As an application of augmented generalized span categories, we introduce the categories $\LagSy$ and $\HamSy$ that respectively provide a categorical framework for the Lagrangian and Hamiltonian descriptions of certain Classical mechanical systems. The morphisms of $\LagSy$ and $\HamSy$ contain all kinematical and dynamical information about these systems and composition of morphisms models the construction of systems from subsystems. A functor from $\LagSy$ to $\HamSy$ translates from the Lagrangian to the Hamiltonian perspective and is a categorical analog of the Legendre transformation
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Open Systems in Classical Mechanics
eScholarship University of California, 2020Co-Authors: Baez, John C., Weisbart David, Yassine AdamAbstract:Span categories provide a framework for formalizing mathematical models of open systems in Classical Mechanics. The categories appearing in Classical Mechanics do not have pullbacks, which requires the use of generalized span categories. We introduce categories $\LagSy$ and $\HamSy$ that respectively provide a categorical framework for the Lagrangian and Hamiltonian descriptions of open Classical mechanical systems. The morphisms of $\LagSy$ and $\HamSy$ correspond to such open systems, and composition of morphisms models the construction of systems from subsystems. The Legendre transformation gives a functor from $\LagSy$ to $\HamSy$ that translates from the Lagrangian to the Hamiltonian perspective
Erik Curiel - One of the best experts on this subject based on the ideXlab platform.
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Classical Mechanics is lagrangian it is not hamiltonian
The British Journal for the Philosophy of Science, 2014Co-Authors: Erik CurielAbstract:One can (for the most part) formulate a model of a Classical system in either the Lagrangian or the Hamiltonian framework. Though it is often thought that those two formulations are equivalent in all important ways, this is not true: the underlying geometrical structures one uses to formulate each theory are not isomorphic. This raises the question whether one of the two is a more natural framework for the representation of Classical systems. In the event, the answer is yes: I state and sketch proofs of two technical results, inspired by simple physical arguments about the generic properties of Classical systems, to the effect that, in a precise sense, Classical systems evince exactly the geometric structure Lagrangian Mechanics provides for the representation of systems, and none that Hamiltonian Mechanics does. The argument not only clarifies the conceptual structure of the two systems of Mechanics, their relations to each other, and their respective mechanisms for representing physical systems. It also shows why naively structural approaches to the representational content of physical theories cannot work.