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R. E. Kastner

Publications and source records attributed to R. E. Kastner.

At least 37 records · Page 2Linked to original sources
arXiv2020

Decoherence and the Transactional Interpretation

This paper presents an analysis of decoherence resulting from the physically real non-unitarity, or 'objective reduction,' that occurs in the Transactional Interpretation (TI). Two distinct aspects of the decoherence process are identified and disambiguated; specifically, (i) the resolution of the basic measurement interaction with respect to the observable under study, and (ii) the effect on the measured system of repetition of the measurement interaction. It is shown that the measurement interaction as described in TI leads naturally to the same quantitative expression for the decoherence function as in the standard unitary-only account. However, unlike in the unitary-only approach, under TI, the reduced density operator for the measured system can legitimately be interpreted as representing the occurrence of an actual measurement result.

quant-ph↗
arXiv2019

The 'Delayed Choice Quantum Eraser' Neither Erases Nor Delays

It is demonstrated that 'quantum eraser' (QE) experiments do not erase any information. Nor do they demonstrate retrocausation or 'temporal nonlocality' in their 'delayed choice' form, beyond standard EPR correlations. It is shown that the erroneous erasure claims arise from assuming that the improper mixed state of the signal photon physically prefers either the 'which way' or 'both ways' basis, when no such preference is warranted. The latter point is illustrated through comparison of the QE spatial state space with the spin-1/2 space of particles in the EPR-spin experiment.

quant-ph↗
arXiv2019

The Relativistic Transactional Interpretation: Immune to the Maudlin Challenge

The Transactional Interpretation has been subject at various times to a challenge based on a type of thought experiment first proposed by Maudlin. It has been argued by several authors that such experiments do not in fact constitute a significant problem for the transactional picture. The purpose of this work is to point out that, when the relativistic level of the interpretation is considered, Maudlin-type challenges cannot even be mounted, since the putative 'slow-moving offer wave,' taken as subject to contingent confirmation, does not exist. This is a consequence of the Davies relativistic quantum-mechanical version of the direct-action theory together with the asymmetry between fermionic field sources and bosonic fields. The Maudlin challenge therefore evaporates completely when the relativistic level of the theory is taken into account.

quant-ph↗
arXiv2018

On Quantum Nonunitarity as a Basis for the Second Law of Thermodynamics

It was first suggested by David Z. Albert that the existence of a real, physical non-unitary process (i.e., "collapse") at the quantum level would yield a complete explanation for the Second Law of Thermodynamics (i.e., the increase in entropy over time). The contribution of such a process would be to provide a physical basis for the ontological indeterminacy needed to derive the irreversible Second Law against a backdrop of otherwise reversible, deterministic physical laws. An alternative understanding of the source of this possible quantum "collapse" or non-unitarity is presented herein, in terms of the Transactional Interpretation (TI). The present model provides a specific physical justification for Boltzmann's often-criticized assumption of molecular randomness (Stosszahlansatz), thereby changing its status from an ad hoc postulate to a theoretically grounded result, without requiring any change to the basic quantum theory. In addition, it is argued that TI provides an elegant way of reconciling, via indeterministic collapse, the time-reversible Liouville evolution with the time-irreversible evolution inherent in so-called "master equations" that specify the changes in occupation of the various possible states in terms of the transition rates between them. The present model is contrasted with the Ghirardi-Rimini-Weber (GRW) "spontaneous collapse" theory previously suggested for this purpose by Albert.

quant-ph↗
arXiv2018

Quantifying Absorption in the Transactional Interpretation

The Transactional Interpretation offers a solution to the measurement problem by identifying specific physical conditions precipitating the non-unitary `measurement transition' of von Neumann. Specifically, the transition occurs as a result of absorber response (a process lacking in the standard approach to the theory). The purpose of this Letter is to make clear that, despite recent claims to the contrary, the concepts of `absorber' and `absorber response,' as well as the process of absorption, are physically and quantitatively well-defined in the transactional picture. In addition, the Born Rule is explicitly derived for radiative processes.

quant-ph↗
arXiv2018

Taking Heisenberg's Potentia Seriously

It is argued that quantum theory is best understood as requiring an ontological duality of res extensa and res potentia, where the latter is understood per Heisenberg's original proposal, and the former is roughly equivalent to Descartes' 'extended substance.' However, this is not a dualism of mutually exclusive substances in the classical Cartesian sense, and therefore does not inherit the infamous 'mind-body' problem. Rather, res potentia and res extensa are proposed as mutually implicative ontological extants that serve to explain the key conceptual challenges of quantum theory; in particular, nonlocality, entanglement, null measurements, and wave function collapse. It is shown that a natural account of these quantum perplexities emerges, along with a need to reassess our usual ontological commitments involving the nature of space and time.

quant-ph↗
arXiv2017

On the Status of the Measurement Problem: Recalling the Relativistic Transactional Interpretation

In view of a resurgence of concern about the measurement problem, it is pointed out that the Relativistic Transactional Interpretation (RTI) remedies issues previously considered as drawbacks or refutations of the original TI. Specifically, once one takes into account relativistic processes that are not representable at the non-relativistic level (such as particle creation and annihilation, and virtual propagation), absorption is quantitatively defined in unambiguous physical terms. In addition, specifics of the relativistic transactional model demonstrate that the Maudlin `contingent absorber' challenge to the original TI cannot even be mounted: basic features of established relativistic field theories (in particular, the asymmetry between field sources and the bosonic fields, and the fact that slow-moving bound states, such as atoms, are not offer waves) dictate that the `slow-moving offer wave' required for the challenge scenario cannot exist. It is concluded that issues previously considered obstacles for TI are no longer legitimately viewed as such, and that reconsideration of the transactional picture is warranted in connection with solving the measurement problem.

quant-ph↗
arXiv2017

Are Dark Energy and Dark Matter Different Aspects of the Same Physical Process?

It is suggested that the apparently disparate cosmological phenomena attributed to so-called 'dark matter' and 'dark energy' arise from the same fundamental physical process: the emergence, from the quantum level, of spacetime itself. This creation of spacetime results in metric expansion around mass points in addition to the usual curvature due to stress-energy sources of the gravitational field. A recent modification of Einstein's theory of general relativity by Chadwick, Hodgkinson, and McDonald incorporating spacetime expansion around mass points, which accounts well for the observed galactic rotation curves, is adduced in support of the proposal. Recent observational evidence corroborates a prediction of the model that the apparent amount of 'dark matter' increases with the age of the universe. In addition, the proposal leads to the same result for the small but nonvanishing cosmological constant, related to 'dark energy, as that of the causet model of Sorkin et al.

gr-qc↗
arXiv2017

From Quantum to Classical Physics: The Role of Distinguishability

The transition from quantum to classical statistics is studied in light of Huggett's finding that the empirical data do not support the usual claim that the distinction between classical and quantum objects consists in the capacity of classical objects to carry permutable labels as opposed to quantum objects. Since permutation of the labels of classical objects counts as a distinct configuration, this feature is usually taken as signifying that classical objects are not identical while quantum objects are. Huggett's finding threatens that characterization of the distinction between classical and quantum objects. The various statistical distributions are examined, and it is found that other distinctions, corresponding to separability and distinguishability, emerge in the classical limit. The role of the chemical potential (the rate of change of the Helmholtz free energy with particle number) is found to be of crucial significance in characterizing this emergence of classicality from the quantum distributions.

quant-ph↗
arXiv2017

Demystifying weak measurements

A large literature has grown up around the proposed use of 'weak measurements' (i.e., unsharp measurements followed by post-selection) to allegedly provide information about hidden ontological features of quantum systems. This paper attempts to clarify the fact that 'weak measurements' involve strong (projective) measurements on one (pointer) member of an entangled system. The only thing 'weak' about such measurements is that the correlation established via the entanglement does not correspond to eigenstates of the 'weakly measured observable' for the remaining component system(s) subject to the weak measurement. All observed statistics are straightforwardly and easily predicted by standard quantum mechanics. Specifically, it is noted that measurement of the pointer steers the remaining degree(s) of freedom into new states with new statistical properties-constituting a non-trivial (even if generally small) disturbance. In addition, standard quantum mechanics readily allows us to conditionalize on a final state if we choose, so the 'post-selection' that features prominently in time-symmetric formulations is also equipment from standard quantum theory. Assertions in the literature that weak measurements leave a system negligibly disturbed, and/or that standard quantum theory is cumbersome for computing the predicted measurement results, are therefore unsupportable, and ontological claims based on such assertions need to be critically reassessed.

quant-ph↗
arXiv2016

Is There Really "Retrocausation" in Time-Symmetric Approaches to Quantum Mechanics?

Time-symmetric interpretations of quantum theory are often presented as featuring "retrocausal" effects in addition to the usual forward notion of causation. This paper examines the ontological implications of certain timesymmetric theories, and finds that no dynamical notion of causation applies to them, either forward or backward. It is concluded that such theories actually describe a static picture, in which the notion of causation is relegated to a descriptor of static relationships among events. In addition, these theories lead to an epistemic rather than ontologically referring, realist view of quantum states.

quant-ph↗
arXiv2016

The Transactional Interpretation and its Evolution into the 21st Century: An Overview

This essay provides a historical, philosophical, and critical overview of the development of the Transactional Interpretation of Quantum Mechanics (TI). It is separated into two parts. Part I presents the history and development of TI from 1986 up to 2016 (the time of writing). Part II lays out current areas of divergence among researchers in TI.

quant-ph↗
arXiv2016

Violation of the Born Rule: Implications for the Classical Electromagnetic Field

It is shown that violation of the Born Rule leads to a breakdown of the correspondence between the quantum electromagnetic field and its classical counterpart. Specifically, the relationship of the quantum coherent state to the classical electromagnetic field turns out to imply that if the Born Rule were violated, this could result in apparent deviations from the energy conservation law applying to the field and its sources (Poynting's Theorem). The result suggests that the Born Rule is just as fundamental a law of Nature as are the conservation laws.

quant-ph↗
arXiv2016

The Illusory Appeal of Decoherence in the Everettian Picture: Affirming the Consequent

The idea that decoherence in a unitary-only quantum theory suffices to explain emergence of classical phenomena has been shown in the peer-reviewed literature to be seriously flawed due to circularity. However, claims continue to be made that this approach, also known as "Quantum Darwinism," is the correct way to understand classical emergence. This Letter reviews the basic problem and points out an additional logical flaw in the argument. It is concluded that the "Quantum Darwinism" program fails.

quant-ph↗
arXiv2016

Beyond Complementarity

It is argued that Niels Bohr ultimately arrived at positivistic and antirealist-flavored statements because of weaknesses in his initial objective of accounting for measurement in physical terms. Bohr's investigative approach faced a dilemma, the choices being (i) conceptual inconsistency or (ii) taking the classical realm as primitive. In either case, Bohr's `Complementarity' does not adequately explain or account for the emergence of a macroscopic, classical domain from a microscopic domain described by quantum mechanics. A diagnosis of the basic problem is offered, and an alternative way forward is indicated.

quant-ph↗
arXiv2016

Bound States as Emergent Quantum Structures

Bound states arise in many interactions among elementary field states, and are represented by poles in the scattering matrix. The emergent nature of bound states suggests that they play a perhaps under-appreciated role in specifying the ontologically relevant degrees of freedom pertaining to composite systems. The basics of this ontology are presented, and it is discussed in light of an example of Arsenijevi\' c et al.

quant-ph↗