scholarly journals The Bundle Theory Approach to Relational Quantum Mechanics

2021 ◽  
Vol 51 (1) ◽  
Author(s):  
Andrea Oldofredi
Keyword(s):  
Quantum Mechanics ◽  
David Hume ◽  
Structural Realism ◽  
Bundle Theory ◽  
Theory Approach ◽  
Relational Quantum Mechanics ◽  
Essential Idea ◽  
Mereological Fusion ◽  
Metaphysical Interpretation ◽  
Aristotelian Tradition

AbstractThe present essay provides a new metaphysical interpretation of Relational Quantum Mechanics (RQM) in terms of mereological bundle theory. The essential idea is to claim that a physical system in RQM can be defined as a mereological fusion of properties whose values may vary for different observers. Abandoning the Aristotelian tradition centered on the notion of substance, I claim that RQM embraces an ontology of properties that finds its roots in the heritage of David Hume. To this regard, defining what kind of concrete physical objects populate the world according to RQM, I argue that this theoretical framework can be made compatible with (i) a property-oriented ontology, in which the notion of object can be easily defined, and (ii) moderate structural realism, a philosophical position where relations and relata are both fundamental. Finally, I conclude that under this reading relational quantum mechanics should be included among the full-fledged realist interpretations of quantum theory.

scholarly journals The Notion of Locality in Relational Quantum Mechanics

2019 ◽  
Vol 49 (2) ◽  
pp. 96-106 ◽  
Author(s):  
P. Martin-Dussaud ◽  
C. Rovelli ◽  
F. Zalamea
Keyword(s):  
Quantum Mechanics ◽  
Relational Quantum Mechanics

scholarly journals How Properties Hold Together in Substances

2016 ◽  
Author(s):  
Joseph E.sr. Earley,
Keyword(s):  
David Hume ◽  
John Locke ◽  
Dynamic Networks ◽  
Structural Realism ◽  
Chemical Research ◽  
Chemical Substances ◽  
Chemical Systems ◽  
Dynamic Structures ◽  
Property Instances ◽  
Philosophical Debates

A main aim of chemical research is to understand how the characteristic properties of specific chemical substances relate to the composition and to the structure of those materials. Such investigations assume a broad consensus regarding basic aspects of chemistry. Philosophers generally regard widespread agreement on basic principles as a remote goal, not something already achieved. They do not agree on how properties stay together in ordinary objects. Some follow John Locke [1632–1704] and maintain that properties of entities inhere in substrates. The item that this approach considers to underlie characteristics is often called “a bare particular” (Sider 2006). However, others reject this understanding and hold that substances are bundles of properties—an approach advocated by David Hume [1711–1776]. Some supporters of Hume’s theory hold that entities are collections of “tropes” (property-instances) held together in a “compresence relationship” (Simons 1994). Recently several authors have pointed out the importance of “structures” for the coherence of substances, but serious questions have been raised about those proposals. Philosophers generally use a time-independent (synchronic) approach and do not consider how chemists understand properties of chemical substances and of dynamic networks of chemical reactions. This chapter aims to clarify how current chemical understanding relates to aspects of contemporary philosophy. The first section introduces philosophical debates, the second considers properties of chemical systems, the third part deals with theories of wholes and parts, the fourth segment argues that closure grounds properties of coherences, the fifth section introduces structural realism (SR), the sixth part considers contextual emergence and concludes that dynamic structures of processes may qualify as determinants (“causes”) of specific outcomes, and the final section suggests that ordinary items are based on closure of relationships among constituents additionally determined by selection for integration into more-extensive coherences. Ruth Garrett Millikan discussed the concept of substance in philosophy: . . . Substances . . . are whatever one can learn from given only one or a few encounters, various skills or information that will apply to other encounters. . . . Further, this possibility must be grounded in some kind of natural necessity. . . . The function of a substance concept is to make possible this sort of learning and use of knowledge for a specific substance. . . . (Millikan 2000, 33)

Identity in Physics

Philosophy ◽  
2014 ◽  
Author(s):  
Décio Krause ◽  
Jonas R. B. Arenhart
Keyword(s):  
Quantum Mechanics ◽  
Classical Mechanics ◽  
Structural Realism ◽  
Exclusion Principle ◽  
Qualitative Properties ◽  
Identity Of Indiscernibles ◽  
Quantum Particles ◽  
Controversial Topic ◽  
The Difference ◽  
The One

Traditionally, the problem of identity is closely associated with the problem of individuality: What is it that makes something being what it is? Approaches to the problem may be classified into two classes: reductionism and transcendental identity. The first group tries to reduce identity to some qualitative feature of the entities dealt with, while the second either grounds identity on some feature other than qualitative properties or else take it to be primitive. The debate is generally centred on the validity of the Principle of the Identity of Indiscernibles (PII), which states that qualitative indiscernibility amounts to numerical identity. If PII is valid, then reductionism concerning identity is at least viable; if PII is invalid, then reductionism seems less plausible and some form of transcendental identity seems required. It is common to say that objects in classical mechanics are individuals. This fact is exhibited by postulating that physical objects obey Maxwell-Boltzmann statistics; if we have containers A and B to accommodate two objects a and b, there are four equiprobable situations: (1) both objects in A, (2) both in B, (3) a in A and b in B, and finally (4) a in B and b in A. Since situations (3) and (4) differ, there may be something that makes the difference—a transcendental individuality or some quality. In quantum mechanics, assuming that we have two containers A and B to accommodate objects a and b, there are just three equiprobable situations for bosons: (1) both objects in A, (2) both in B, (3) one object in A and one in B. It makes no sense to say that it is a or b that is in A: Switching them makes no difference. For fermions we have only one possibility due to the exclusion principle: (1) one object in A and one in B. Again, switching them makes no difference whatsoever. The dispute in quantum mechanics concerns non-individuality on the one side and individuality (be it reductionism or transcendental individuality) on the other. That distinction was grounded on the fact that quantum particles may be qualitatively indiscernible, and, as the statistics show, permutations are unobservable. The actual debate concerns whether some form of reductionism may survive in quantum mechanics or whether some form of transcendental identity should be adopted on the one hand and whether non-individuality is a viable option. Furthermore, a third option, Ontic Structural Realism (OSR), proposes that we transcend the debate and choose a metaphysics of structures and relations, leaving the controversial topic individuals × non-individuals behind.

scholarly journals Relational Quantum Mechanics and Probability

2018 ◽  
Vol 48 (9) ◽  
pp. 1092-1111 ◽  
Author(s):  
M. Trassinelli
Keyword(s):  
Quantum Mechanics ◽  
Relational Quantum Mechanics

scholarly journals Path Integral Implementation of Relational Quantum Mechanics

2021 ◽  
Author(s):  
Jianhao M. Yang
Keyword(s):  
Quantum Mechanics ◽  
Quantum System ◽  
Path Integral ◽  
Measurement Theory ◽  
Entanglement Entropy ◽  
Quantum Probability ◽  
Probability Amplitude ◽  
Path Integral Representation ◽  
Relational Quantum Mechanics ◽  
Influence Functional

Abstract Relational formulation of quantum mechanics is based on the idea that relational properties among quantum systems, instead of the independent properties of a quantum system, are the most fundamental elements to construct quantum mechanics. In the recent works (J. M. Yang, Sci. Rep. 8:13305, 2018), basic relational quantum mechanics framework is formulated to derive quantum probability, Born's Rule, Schr\"{o}dinger Equations, and measurement theory. This paper gives a concrete implementation of the relational probability amplitude by extending the path integral formulation. The implementation not only clarifies the physical meaning of the relational probability amplitude, but also gives several important applications. For instance, the double slit experiment can be elegantly explained. A path integral representation of the reduced density matrix of the observed system can be derived. Such representation is shown valuable to describe the interaction history of the measured system and a series of measuring systems. More interestingly, it allows us to develop a method to calculate entanglement entropy based on path integral and influence functional. Criteria of entanglement is proposed based on the properties of influence functional, which may be used to determine entanglement due to interaction between a quantum system and a classical field.

scholarly journals Branch-counting in the Everett interpretation of quantum mechanics

2021 ◽  
Vol 477 (2255) ◽  
Author(s):  
Simon Saunders
Keyword(s):  
Quantum Mechanics ◽  
Ad Hoc ◽  
Quantum Probability ◽  
Objective Probability ◽  
Theory Approach ◽  
Interpretation Of Quantum Mechanics ◽  
Many Worlds ◽  
Everett Interpretation ◽  
Counting Rule ◽  
Bose Einstein

A defence is offered of a version of the branch-counting rule in the Everett interpretation (otherwise known as many worlds interpretation) of quantum mechanics that both depends on the state and is continuous in the norm topology on Hilbert space. The well-known branch-counting rule, for realistic models of measurements, in which branches are defined by decoherence theory, fails this test. The new rule hinges on the use of decoherence theory in defining branching structure, and specifically decoherent histories theory. On this basis ratios of branch numbers are defined, free of any convention. They agree with the Born rule and deliver a notion of objective probability similar to naive frequentism, save that the frequencies of outcomes are not confined to a single world at different times, but spread over worlds at a single time. Nor is it ad hoc : it is recognizably akin to the combinatorial approach to thermodynamic probability, as introduced by Boltzmann in 1879. It is identical to the procedure followed by Planck, Bose, Einstein and Dirac in defining the equilibrium distribution of the Bose–Einstein gas. It also connects in a simple way with the decision-theory approach to quantum probability.

Miracles and Models: Why reports of the death of Structural Realism may be exaggerated

2007 ◽  
Vol 61 ◽  
pp. 125-154
Author(s):  
John Worrall
Keyword(s):  
Quantum Mechanics ◽  
General Theory ◽  
Scientific Realism ◽  
Final Section ◽  
Recent Literature ◽  
Structural Realism ◽  
Theory Of Relativity ◽  
Scientific Theories ◽  
General Theory Of Relativity ◽  
The Third

What is it reasonable to believe about our most successful scientific theories such as the general theory of relativity or quantum mechanics? That they are true, or at any rate approximately true? Or only that they successfully ‘save the phenomena’, by being ‘empirically adequate’? In earlier work I explored the attractions of a view called Structural Scientific Realism (hereafter: SSR). This holds that it is reasonable to believe that our successful theories are (approximately) structurally correct (and also that this is the strongest epistemic claim about them that it is reasonable to make). In the first part of this paper I shall explain in some detail what this thesis means and outline the reasons why it seems attractive. The second section outlines a number of criticisms that have none the less been brought against SSR in the recent (and as we shall see, in some cases, not so recent) literature; and the third and final section argues that, despite the fact that these criticisms might seem initially deeply troubling (or worse), the position remains viable.

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