scholarly journals On individuality in quantum theory

2015 ◽  
Vol 13 (1) ◽  
pp. 29-38
Author(s):  
Jasmina Jeknic-Dugic
Keyword(s):  
Quantum Theory ◽  
Structural Realism ◽  
Mechanical Analysis ◽  
Quantum Systems ◽  
Quantum Mechanical ◽  
Ontic Structural Realism

A quantum mechanical analysis of the decomposability of quantum systems into subsystems provides support for the so-called "attenuated Eliminative Ontic Structural Realism" within Categorical Structuralism studies in physics. Quantum subsystems are recognized as non-individual, relationally defined objects that deflate or relax some standard objections against Eliminative Ontic Structural Realism. Our considerations assume the universally valid quantum theory without tackling interpretational issues.

Particle populations and number operators in quantum theory

1972 ◽  
Vol 4 (01) ◽  
pp. 39-80 ◽  
Author(s):  
J. E. Moyal
Keyword(s):  
Statistical Theory ◽  
Quantum Theory ◽  
Subsequent Development ◽  
Quantum Systems ◽  
Quantum Mechanical ◽  
Subsequent Work ◽  
Von Neumann ◽  
Quantum Mechanical Representation ◽  
Finite Particle ◽  
Number Of Particles

The purpose of the present paper is to give a general theory of the quantum mechanical representation of particle populations.The first part of the paper, Sections 1 to 5, is devoted to a review of mathematical principles of quantum theory, with particular emphasis on the role played by probability concepts, using an approach adapted to the subsequent development of the theory of particle populations. This approach, which goes back in its essentials to von Neumann [20], leans heavily on the subsequent work of Wigner, Mackey, Jauch, Segal, Wightman and many others (see e.g., Mackey [15], Jauch [11], Streater and Wightman [26]). Sections 6 to 9 deal with the representation of finite particle populations: i.e., quantum systems where the total number of particles is an observable. In Section 10 a brief sketch is given of the generalization of the theory to infinite populations where the total number of particles is not an observable, as e.g., in the statistical theory of an infinitely extended gas (see Ruelle [22]). Finally, Section 11 treats some simple examples.

Particle populations and number operators in quantum theory

1972 ◽  
Vol 4 (1) ◽  
pp. 39-80 ◽  
Author(s):  
J. E. Moyal
Keyword(s):  
Statistical Theory ◽  
Quantum Theory ◽  
Subsequent Development ◽  
Quantum Systems ◽  
Quantum Mechanical ◽  
Subsequent Work ◽  
Von Neumann ◽  
Quantum Mechanical Representation ◽  
Finite Particle ◽  
Number Of Particles

The purpose of the present paper is to give a general theory of the quantum mechanical representation of particle populations.The first part of the paper, Sections 1 to 5, is devoted to a review of mathematical principles of quantum theory, with particular emphasis on the role played by probability concepts, using an approach adapted to the subsequent development of the theory of particle populations. This approach, which goes back in its essentials to von Neumann [20], leans heavily on the subsequent work of Wigner, Mackey, Jauch, Segal, Wightman and many others (see e.g., Mackey [15], Jauch [11], Streater and Wightman [26]). Sections 6 to 9 deal with the representation of finite particle populations: i.e., quantum systems where the total number of particles is an observable. In Section 10 a brief sketch is given of the generalization of the theory to infinite populations where the total number of particles is not an observable, as e.g., in the statistical theory of an infinitely extended gas (see Ruelle [22]). Finally, Section 11 treats some simple examples.

Asymmetric Time Evolution and Reduced Dynamics

2011 ◽  
Vol 18 (02) ◽  
pp. 157-163
Author(s):  
Peter W. Bryant
Keyword(s):  
Quantum Theory ◽  
Time Evolution ◽  
Open Quantum Systems ◽  
Quantum Systems ◽  
Quantum Mechanical ◽  
Time Coordinate ◽  
Mechanical Environment ◽  
Measurable Difference ◽  
Asymmetric Quantum ◽  
Symmetric Theory

When using a time asymmetric quantum theory, one must identify the time evolution parameter with a duration in time rather than with a time coordinate value. This identification restricts the options for the quantum mechanical environment of open quantum systems. The restriction may be important for interpretational questions concerning irreversibility or entanglement, but there is no measurable difference between a reduced dynamics within a time symmetric theory or within a time asymmetric theory.

Operators and meaning of wave function

2016 ◽  
pp. 4039-4042
Author(s):  
Viliam Malcher
Keyword(s):  
Wave Function ◽  
Quantum Theory ◽  
State Vector ◽  
The State ◽  
Physical Significance ◽  
Central Problem ◽  
Quantum Mechanical ◽  
Mechanical Description ◽  
Quantum Mechanical Description ◽  
Interpretation Of Quantum Theory

The interpretation problems of quantum theory are considered. In the formalism of quantum theory the possible states of a system are described by a state vector. The state vector, which will be represented as |ψ> in Dirac notation, is the most general form of the quantum mechanical description. The central problem of the interpretation of quantum theory is to explain the physical significance of the |ψ>. In this paper we have shown that one of the best way to make of interpretation of wave function is to take the wave function as an operator.

The Necessity of Sufficiency

2018 ◽  
Author(s):  
Bruce L. Gordon
Keyword(s):  
Recent Work ◽  
Quantum Physics ◽  
Structural Realism ◽  
Sufficient Reason ◽  
Divine Action ◽  
Ontic Structural Realism ◽  
Existence Of God ◽  
Principle Of Sufficient Reason ◽  
Adequate Understanding ◽  
Quantum Phenomena

There is an argument for the existence of God from the incompleteness of nature that is vaguely present in Plantinga’s recent work. This argument, which rests on the metaphysical implications of quantum physics and the philosophical deficiency of necessitarian conceptions of physical law, deserves to be given a clear formulation. The goal is to demonstrate, via a suitably articulated principle of sufficient reason, that divine action in an occasionalist mode is needed (and hence God’s existence is required) to bring causal closure to nature and render it ontologically functional. The best explanation for quantum phenomena and the most adequate understanding of general providence turns out to rest on an ontic structural realism in physics that is grounded in the immaterialist metaphysics of theistic idealism.

Entanglement

2017 ◽  
Author(s):  
Richard Healey
Keyword(s):  
Quantum Theory ◽  
Quantum State ◽  
Physical Condition ◽  
Physical System ◽  
Polarization State ◽  
Quantum Systems ◽  
Ghz State ◽  
Mathematical Representation ◽  
Entangled State ◽  
Physical Relation

Often a pair of quantum systems may be represented mathematically (by a vector) in a way each system alone cannot: the mathematical representation of the pair is said to be non-separable: Schrödinger called this feature of quantum theory entanglement. It would reflect a physical relation between a pair of systems only if a system’s mathematical representation were to describe its physical condition. Einstein and colleagues used an entangled state to argue that its quantum state does not completely describe the physical condition of a system to which it is assigned. A single physical system may be assigned a non-separable quantum state, as may a large number of systems, including electrons, photons, and ions. The GHZ state is an example of an entangled polarization state that may be assigned to three photons.

scholarly journals Generalization of intrinsic ductile-to-brittle criteria by Pugh and Pettifor for materials with a cubic crystal structure

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
O. N. Senkov ◽  
D. B. Miracle
Keyword(s):  
Crystal Structure ◽  
Shear Modulus ◽  
Bulk Modulus ◽  
Single Crystal ◽  
Elastic Constants ◽  
Mechanical Analysis ◽  
Quantum Mechanical ◽  
Modulus Ratio ◽  
Cubic Crystal ◽  
The Difference

AbstractTwo classical criteria, by Pugh and Pettifor, have been widely used by metallurgists to predict whether a material will be brittle or ductile. A phenomenological correlation by Pugh between metal brittleness and its shear modulus to bulk modulus ratio was established more than 60 years ago. Nearly four decades later Pettifor conducted a quantum mechanical analysis of bond hybridization in a series of intermetallics and derived a separate ductility criterion based on the difference between two single-crystal elastic constants, C12–C44. In this paper, we discover the link between these two criteria and show that they are identical for materials with cubic crystal structures.

‘Scale Relative Ontology’ and Scientism

2015 ◽  
Vol 23 (46) ◽  
pp. 99-118
Author(s):  
Noel Boulting ◽  
Keyword(s):  
Structural Realism ◽  
Ontic Structural Realism ◽  
The Way

Ladyman and Ross’s Every Thing Must Go is a challenging text. In order to ascertain its significance, attention will be focused on their idea of Scale Relative Ontology. To do this their conception of Ontic Structural Realism will require elucidation. Its implications for Scale Relative Ontology will be explored before considering the way Scale Relative Ontology can be cast through three possible dimensions: the cosmological, the ordinary middle-sized, and scientific perspectives. In exploring the latter perspective, and applying insights derived from Peirce’s philosophy, their defence of Scientism will then be considered. In this way three different senses can be distinguished through which this doctrine can be presented, before examining what kind of Scientism they advocate and thereby its adequacy.

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