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R. E. Kastner

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

At least 19 recordsLinked to original sources
arXiv2026

Maxwell's Demon

This work provides an overview of key historical developments in the formulation of the Second Law of Thermodynamics, focusing on the notorious challenge of ``Maxwell's Demon'', a hypothetical creature who could presumably violate that law. It begins by recalling Maxwell's challenge and discussing the apparent loophole in the Second Law that appears to make such a violation possible. An alternative formulation of the Demon challenge by Szilard is considered, along with his attempted defeat of the Demon through reference to measurement. A similar effort by Brillouin is also analyzed. The proposal of Bennett to defeat the Demon through the requirement of memory erasure is critically discussed. Finally, it is proposed that the Second Law gains a firm foundation through neglected features of quantum theory. In particular, an application of the Heisenberg Uncertainty Principle is shown to decisively defeat the Demon, as well as to serve as justification for Landauer's Principle, albeit in terms distinct from the usual computational formulation.

quant-ph↗
arXiv2026

The Physics Behind Symmetrization

It is often asserted that quantum states for same-type particles must be symmetrized due to ``label redundancy,'' i.e. the assumption that the permutations of labels in direct-product states do not reflect any real physical distinction and thus their permutations constitute an ``exchange degeneracy''. This assumption is directly challenged by the case of scattering of same-type particles such as electrons, which involves two physically distinct scattering channels effectively corresponding to permutation of the labels. I discuss this counterexample with critical attention to an extant portrayal in the literature that omits pertinent physical content. I further note ways in which the assumption that symmetrization must be universally imposed is not supported by actual calculations of particle interactions, nor by seemingly viable particle states based on preparations and outcomes.

quant-ph↗
arXiv2026

Agent Choice via Quantum Flux in Living Systems

A basic model is provided that places active, intentional choices by biological organisms on a solid physical footing. The model is provisionally called "Agent Choice via Quantum Flux." It brings to bear specific physics on living systems in a way that allows for intentional choices not pre-determined by physical laws, but remaining consistent with those laws. It does so by exploring a possible many-to-one relation of quantum states to agent choices, with a parallel to the relation of thermodynamic microstates to macrostates.

quant-ph↗
arXiv2025

Where Photons Have Been: Nowhere Without All Components of Their Wavefunctions

A nested interferometer experiment by Danan et al (2013) is discussed and some claims evaluated concerning the whereabouts of the photon, primarily in the context of time-symmetric interpretations of quantum theory including the Two-State Vector Formalism (TSVF) and the Transactional Interpretation (TI). It is pointed out that the TSVF account fails to predict the observed data based only on the first-order wavefunction component. It is shown that the Transactional Interpretation readily accounts for all the observed phenomena.

quant-ph↗
arXiv2025

Maxwell's Demon Is Foiled by the Entropy Cost of Measurement, Not Erasure

I dispute the conventional claim that the second law of thermodynamics is saved from a "Maxwell's Demon" by the entropy cost of information erasure, and show that instead it is measurement that incurs the entropy cost. Thus Brillouin, who identified measurement as savior of the second law, was essentially correct, and putative refutations of his view, such as Bennett's claim to measure without entropy cost, are seen to fail when the applicable physics is taken into account. I argue that the tradition of attributing the defeat of Maxwell's Demon to erasure rather than to measurement arose from unphysical classical idealizations that do not hold for real gas molecules, as well as a physically ungrounded recasting of physical thermodynamical processes into computational and information-theoretic conceptualizations. I argue that the fundamental principle that saves the second law is the quantum uncertainty principle applying to the need to localize physical states to precise values of observables in order to effect the desired disequilibria aimed at violating the second law. I obtain the specific entropy cost for localizing a molecule in the Szilard engine and show that it coincides with the quantity attributed to Landauer's principle. I also note that an experiment characterized as upholding an entropy cost of erasure in a "quantum Maxwell's Demon" actually demonstrates an entropy cost of measurement.

quant-ph↗
arXiv2024

A Model of Entropy Production

A key tenet of the Transactional Interpretation of Quantum Mechanics is the idea that photon absorption localizes the absorbing material system. In doing so, it measures the location of the absorber and hence reduces information entropy, which in turn needs to be balanced by appropriate entropy production, if there is a link between information entropy and thermodynamic entropy. Based on a critical analysis of the physics of information erasure, we clarify the link between information and thermodynamic entropy and develop a rigorous model of entropy production in photon absorption processes. Links to the intepretation of quantum probabilities and Maxwell's Demon are made.

quant-ph↗
arXiv2024

The Quantum Master and its Classical Emissary

Ian McGilchrist's works present the thesis that the two hemispheres of the brain have radically different modes of interacting with the world, and that their respective perceptions and functions must be properly integrated for a viable way forward. This proper integration requires restoring the right-brain to its proper place as "Master." I discuss a parallel to this insight in the dichotomous "worlds" of quantum and classical physics. In addition, I discuss the relevance of Whitehead's process philosophy, as well as the Taoist concepts of Yin and Yang, with particular attention to the importance and primacy of Yin underlying the quantum level as "Master."

physics.hist-ph↗
arXiv2024

Conventional Quantum Theory Does Not Support A Coherent Relational Account

Quantum theory in its conventional formulation is notoriously subject to various measurement-related paradoxes, as exemplified by the "Schrodinger's Cat" and "Wigner's Friend" thought experiments. It has been shown, for example by Frauchiger and Renner, that nested measurements such as those occurring in the Wigner's Friend experiment can lead to inconsistencies concerning the putative outcomes of measurements. Such inconsistencies are commonly presumed to remain private and incommensurable, but this is not the case. A counterexample, in which the inconsistencies can be revealed among the observers, is reviewed. The implications for a recent attempt to shield Relational Quantum Mechanics from such inconsistencies are considered, and it is concluded that the attempt is not successful. Further implications for the state of the debate concerning the viability of quantum theory in its various formulations are discussed.

quant-ph↗
arXiv2024

The Arrow of Time is Alive and Well but Forbidden Under the Received View of Physics

This essay offers a meta-level analysis in the sociology and history of physics in the context of the so-called "Arrow of Time Problem" or "Two Times Problem," which asserts that the empirically observed directionality of time is in conflict with physical theory. I argue that there is actually no necessary conflict between physics and the arrow of time, and that the observed directionality of time is perfectly consistent with physics unconstrained by certain optional metaphysical, epistemological and methodological beliefs and practices characterizing the conventional or Received View.

physics.hist-ph↗
arXiv2024

A Note on the Origin of Inertia

The question of where the inertial properties of matter come from has been open for a long time. Isaac Newton considered inertia an intrinsic property of matter. Ernst Mach held a different view whereby the inertia of a body comes from its interaction with the rest of the universe. This idea is known today as Mach's principle. We discuss Mach's principle based on transactional gravity, the recently developed completion of the entropic gravity program by the physics of quantum events induced by transactions. A consequence of the analysis is a fundamental relation between the gravitational constant G and the total mass in the causal universe, derived by means of entropic principles.

gr-qc↗
arXiv2024

Entropy Cost of "Erasure" in Physically Irreversible Processes

A restricted form of Landauer's Principle, independent of computational considerations, is shown to hold for thermal systems by reference to the joint entropy associated with conjugate observables. It is shown that the source of the compensating entropy for irreversible physical processes is due to the ontological uncertainty attending values of such mutually incompatible observables, rather than due to epistemic uncertainty as traditionally assumed in the information-theoretic approach. In particular, it is explicitly shown that erasure of logical (epistemic) information via reset operations is not equivalent to erasure of thermodynamic entropy, so that the traditional, information-theoretic form of Landauer's Principle is not supported by the physics. A further implication of the analysis is that, in principle, there can be no Maxwell's Demon in the real world.

quant-ph↗
arXiv2023

Gravity from Transactions: Fulfilling the Entropic Gravity Program

This is a review of new developments in entropic gravity in light of the Relativistic Transactional Interpretation (RTI). A transactional approach to spacetime events can give rise in a natural way to entropic gravity (in the way originally proposed by Erik Verlinde) while also overcoming extant objections to that research program. The theory also naturally gives rise to a Cosmological Constant and to Modified Newtonian Dynamics (MOND) and thus provides a physical explanation for the phenomena historically attributed to "dark energy" and "dark matter".

gr-qc↗
arXiv2023

Quantum Theory Needs (And Probably Has) Real Reduction

The traditional, standard approach to quantum theory is to assume that the theory ``really'' contains only unitary physical dynamics--i.e., that the only physically quantifiable evolution is that given by the time-dependent Schrodinger equation. This leads to two distinct classes of interpretations for the standard theory in its orthodox form: (i) an Everettian-type approach assuming that all mutually exclusive outcomes occur in different ``branches'' of the universe; or (ii) single-outcome approaches that assume a ``projection postulate'' (PP) with no accompanying physical account within quantum theory. A contrasting, unorthodox approach is to suggest forms of quantum theory that involve physical non-unitarity; these are called ``objective collapse models.'' Among these are Penrose's theory of gravitation-induced collapse and the Transactional Interpretation. The primary focus of this paper is an example demonstrating that standard quantum theory (with or without the projection postulate) can in-principle yield empirically consequential inconsistencies. Thus, it appears that for quantum theory to be viable in a realist sense (as opposed to being an instrumentalist protocol in which inconsistencies are evaded by changing the protocol), it must possess genuine, physical non-unitarity yielding well-defined single outcomes. This leads to the conclusion that objective collapse models should be more seriously considered.

quant-ph↗
arXiv2023

Unitary Interactions Do Not Yield Outcomes: Attempting to Model "Wigner's Friend"

An experiment by Proietti {\it et al} purporting to instantiate the `Wigner's Friend' thought experiment is discussed. It is pointed out that the stated implications of the experiment regarding the alleged irreconcilability of facts attributed to different observers warrant critical review. In particular, violation of a Clauser-Horne-Shimony inequality by the experimental data actually shows that the attribution of measurement outcomes to the ``Friends'' (modeled by internal photons undergoing unitary interactions) is erroneous. An elementary but often overlooked result regarding improper mixtures is adduced in support of this assessment. A counterexample is provided which refutes the popular notion that quantum theory leads to `relative facts' that never manifest as empirical inconsistencies. It is further noted that under an assumption of unbroken unitarity, no measurement correlation can ever yield an outcome, since all systems remain in improper mixtures, and attributing a definite but unknown outcome contradicts their composite pure state. It is pointed out that there already exists a solution to this conundrum in the form of an alternative formulation of quantum theory, which accounts for the data showing that no outcomes occurred at the interior entangled photon level and also predicts that outcomes can and do occur at the exterior ``super-observer'' level in this type of experiment.

quant-ph↗
arXiv2021

The Relativistic Transactional Interpretation and The Quantum Direct-Action Theory

This paper presents key aspects of the quantum relativistic direct-action theory that underlies the Relativistic Transactional Interpretation. It notes some crucial ways in which traditional interpretations of the direct-action theory have impeded progress in developing its quantum counterpart. Specifically, (1) the so-called 'light tight box' condition is re-examined and it is shown that the quantum version of this condition is much less restrictive than has long been assumed; and (2) the notion of a 'real photon' is disambiguated and revised to take into account that real (on-shell) photons are indeed both emitted and absorbed and therefore have finite lifetimes. Also discussed is the manner in which real, physical non-unitarity naturally arises in the quantum direct-action theory of fields, such that the measurement transition can be clearly defined from within the theory, without reference to external observers and without any need to modify quantum theory itself. It is shown that field quantization arises from the non-unitary interaction.

quant-ph↗
arXiv2021

The Relativistic Transactional Interpretation and Spacetime Emergence

We consider the manner in which the spacetime manifold emerges from a quantum substratum through the transactional process, in which spacetime events and their connections are established. In this account, there is no background spacetime as is generally assumed in physical theorizing. Instead, the usual notion of a background spacetime is replaced by the quantum substratum, comprising quantum systems with nonvanishing rest mass. Rest mass corresponds to internal periodicities that function as internal clocks defining proper times, and in turn, inertial frames that are not themselves aspects of the spacetime manifold, but are pre-spacetime reference structures. Specific processes in the quantum substratum serve to distinguish absolute from relative motion.

gr-qc↗
arXiv2021

Unitary-Only Quantum Theory Cannot Consistently Describe the Use of Itself: On the Frauchiger-Renner Paradox

The Frauchiger-Renner Paradox is an extension of paradoxes based on the 'Problem of Measurement,' such as Schrodinger's Cat and Wigner's Friend. All of these paradoxes stem from assuming that quantum theory has only unitary (linear) physical dynamics, and the attendant ambiguity about what counts as a 'measurement'--i.e., the inability to account for the observation of determinate measurement outcomes from within the theory itself. This paper discusses a basic inconsistency arising in the FR scenario at a much earlier point than the derived contradiction: namely, the inconsistency inherent in treating an improper mixture (reduced density operator) as a proper, epistemic mixture. This is an illegitimate procedure that is nevertheless endemic if quantum theory is assumed to be always unitary. In contrast, under a non-unitary account of quantum state reduction yielding determinate outcomes, the use of a proper mixture for measurement results becomes legitimate, and this entire class of paradoxes cannot be mounted. The conclusion is that the real lesson of the FR paradox is that it is the unitary-only assumption that needs to be critically reassessed.

quant-ph↗