Particle Creation and Annihilation: Two Bohmian Approaches

This paper reviews and discusses two extensions of Bohmian Mechanics to the phenomena of particle creation and annihilation typically observed in Quantum Field Theory (QFT): the so-called Bell-type Quantum Field Theory and the Dirac Sea representation. These theories have a secure metaphysical basis as they postulate a particle ontology while satisfying the requirements imposed by the Primitive Ontology approach to quantum physics. Furthermore, their methodological perspective intentionally provides a set of rules to immunize physical theories to the conceptual and technical problems plaguing the standard formulation of Quantum Mechanics and QFT. A metaphysical analysis of both theories will be given, emphasizing the relevant features of each proposal. Finally, it will be acknowledged that, despite the metaphysical virtues and niceties of these frameworks, ultimately they do not provide definitive answers to other cogent foundational issues in QFT. Thus, these theories (as well as the other Bohmian extensions to QFT) should be considered as partial solutions to the problems raised by the quantum theory of fields. This situation can be considered incentive for further research

Some remarks on the mentalistic reformulation of the measurement problem. A reply to S. Gao

Gao (2017) presents a new mentalistic reformulation of the well-known measurement problem affecting the standard formulation of quantum mechanics. According to this author, it is essentially a determinate-experience problem, namely a problem about the compatibility between the linearity of the Schrödinger’s equation, the fundamental law of quantum theory, and definite experiences perceived by conscious observers. In this essay I aim to clarify (i) that the well-known measurement problem is a mathematical consequence of quantum theory’s formalism, and that (ii) its mentalistic variant does not grasp the relevant causes which are responsible for this puzzling issue. The first part of this paper will be concluded claiming that the “physical” formulation of the measurement problem cannot be reduced to its mentalistic version. In the second part of this work it will be shown that, contrary to the case of quantum mechanics, Bohmian mechanics and GRW theories provide clear explanations of the physical processes responsible for the definite localization of macroscopic objects and, consequently, for well-defined perceptions of measurement outcomes by conscious observers. More precisely, the macro-objectification of states of experimental devices is obtained exclusively in virtue of their clear ontologies and dynamical laws without any intervention of human observers. Hence, it will be argued that in these theoretical frameworks the measurement problem and the determinate-experience problem are logically distinct issues

Particle Creation and Annihilation: Two Bohmian Approaches

This paper reviews and discusses two extensions of Bohmian Mechanics to the phenomena of particle creation and annihilation typically observed in Quantum Field Theory (QFT): the so-called Bell-type Quantum Field Theory and the Dirac Sea representation. These theories have a secure metaphysical basis as they postulate a particle ontology while satisfying the requirements imposed by the Primitive Ontology approach to quantum physics. Furthermore, their methodological perspective intentionally provides a set of rules to immunize physical theories to the conceptual and technical problems plaguing the standard formulation of Quantum Mechanics and QFT. A metaphysical analysis of both theories will be given, emphasizing the relevant features of each proposal. Finally, it will be acknowledged that, despite the metaphysical virtues and niceties of these frameworks, ultimately they do not provide definitive answers to other cogent foundational issues in QFT. Thus, these theories (as well as the other Bohmian extensions to QFT) should be considered as partial solutions to the problems raised by the quantum theory of fields. This situation can be considered incentive for further research

Is Quantum Mechanics Self-Interpreting?

Fuchs and Peres (2000) claimed that standard Quantum Mechanics needs no interpretation. In this essay, I show the flaws of the arguments presented in support to this thesis. Specifically, it will be claimed that the authors conflate QM with Quantum Bayesianism (QBism) - the most prominent subjective formulation of quantum theory; thus, they endorse a specific interpretation of the quantum formalism. Secondly, I will explain the main reasons for which QBism should not be considered a physical theory, being it concerned exclusively with agents’ beliefs and silent about the physics of the quantum regime. Consequently, the solutions to the quantum puzzles provided by this approach cannot be satisfactory from a physical perspective. In the third place, I evaluate Fuchs and Peres arguments contra the non-standard interpretations of QM, showing again the fragility of their claims. Finally, it will be stressed the importance of the interpretational work in the context of quantum theory

Some remarks on the mentalistic reformulation of the measurement problem. A reply to S. Gao

Gao (2017) presents a new mentalistic reformulation of the well-known measurement problem affecting the standard formulation of quantum mechanics. According to this author, it is essentially a determinate-experience problem, namely a problem about the compatibility between the linearity of the Schroedinger's equation, the fundamental law of quantum theory, and definite experiences perceived by conscious observers. In this essay I aim to clarify (i) that the well-known measurement problem is a mathematical consequence of quantum theory's formalism, and that (ii) its mentalistic variant does not grasp the relevant causes which are responsible for this puzzling issue. The first part of this paper will be concluded claiming that the "physical" formulation of the measurement problem cannot be reduced to its mentalistic version. In the second part of this work it will be shown that, contrary to the case of quantum mechanics, Bohmian mechanics and GRW theories provide clear explanations of the physical processes responsible for the definite localization of macroscopic objects and, consequently, for well-defined perceptions of measurement outcomes by conscious observers. More precisely, the macro-objectification of states of experimental devices is obtained exclusively in virtue of their clear ontologies and dynamical laws without any intervention of human observers. Hence, it will be argued that in these theoretical frameworks the measurement problem and the determinate-experience problem are logically distinct issues

No-Go Theorems and the Foundations of Quantum Physics

In the history of quantum physics several no-go theorems have been proved, and many of them have played a central role in the development of the theory, such as Bell’s or the Kochen–Specker theorem. A recent paper by F. Laudisa has raised reasonable doubts concerning the strategy followed in proving some of these results, since they rely on the standard framework of quantum mechanics, a theory that presents several ontological problems. The aim of this paper is twofold: on the one hand, I intend to reinforce Laudisa’s methodological point by critically discussing Malament’s theorem in the context of the philosophical foundation of quantum field theory; secondly, I rehabilitate Gisin’s theorem showing that Laudisa’s concerns do not apply to it

Relational Quantum Mechanics and the PBR Theorem: A Peaceful Coexistence

According to Relational Quantum Mechanics (RQM) the wave function $\psi$ is considered neither a concrete physical item evolving in spacetime, nor an object representing the absolute state of a certain quantum system. In this interpretative framework, $\psi$ is defined as a computational device encoding observers' information; hence, RQM offers a somewhat epistemic view of the wave function. This perspective seems to be at odds with the PBR theorem, a formal result excluding that wave functions represent knowledge of an underlying reality described by some ontic state. In this paper we argue that RQM is not affected by the conclusions of PBR's argument; consequently, the alleged inconsistency can be dissolved. To do that, we will thoroughly discuss the very foundations of the PBR theorem, i.e. Harrigan and Spekkens' categorization of ontological models, showing that their implicit assumptions about the nature of the ontic state are incompatible with the main tenets of RQM. Then, we will ask whether it is possible to derive a relational PBR-type result, answering in the negative. This conclusion shows some limitations of this theorem not yet discussed in the literature

Particle Creation and Annihilation: Two Bohmian Approaches

This paper reviews and discusses two extensions of Bohmian Mechanics to the phenomena of particle creation and annihilation typically observed in Quantum Field Theory (QFT): the so-called Bell-type Quantum Field Theory and the Dirac Sea representation. These theories have a secure metaphysical basis as they postulate a particle ontology while satisfying the requirements imposed by the Primitive Ontology approach to quantum physics. Furthermore, their methodological perspective intentionally provides a set of rules to immunize physical theories to the conceptual and technical problems plaguing the standard formulation of Quantum Mechanics and QFT. A metaphysical analysis of both theories will be given, emphasizing the relevant features of each proposal. Finally, it will be acknowledged that, despite the metaphysical virtues and niceties of these frameworks, ultimately they do not provide definitive answers to other cogent foundational issues in QFT. Thus, these theories (as well as the other Bohmian extensions to QFT) should be considered as partial solutions to the problems raised by the quantum theory of fields. This situation can be considered incentive for further research