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The experiment performed by Henry Cavendish to measure the density of the earth, is in numerous textbooks described as a measurement of the universal gravitational constant, G, even if we know that this was not true. In this paper, a study on how common this "myth" is based on the checklist developed by Leite on a total of 84 textbooks. The prevalence of the myth in most textbooks throughout the 20th century indicates a focus on the contemporary interests of authors and the physics community in presenting the development of physics. An explanation of the prevalence of the myth and a different approach, Comment: 14 pages

The present article examines a system of four-valued logic recently introduced by Oleg Grigoriev and Dmitry Zaitsev. In particular, besides other interesting results, we will clarify the connection of this system to related systems developed by Paul Ruet and Norihiro Kamide. By doing so, we discuss two philosophical problems that arise from making such connections quite explicit: first, there is an issue with how to make intelligible the meaning of the connectives and the nature of the truth values involved in the many-valued setting employed -- what we have called `the Haackian theme'. We argue that this can be done in a satisfactory way, when seen according to the classicist's light. Second, and related to the first problem, there is a complication arising from the fact that the proof system advanced may be made sense of by advancing at least four such different and incompatible readings -- a sharpening of the so-called `Carnap problem'. We make explicit how the problems connect with each other precisely and argue that what results is a kind of underdetermination by the deductive apparatus for the system., Comment: In Proceedings NCL'24, arXiv:2412.20053

In this paper, we elaborate on the ordered-pair semantics originally presented by Matthew Clemens for LP (Priest's Logic of Paradox). For this purpose, we build on a generalization of Clemens semantics to the case of n-tuple semantics, for every n. More concretely, i) we deal with the case of a language with quantifiers, and ii) we consider philosophical implications of the semantics. The latter includes, first, a reading of the semantics in epistemic terms, involving multiple agents. Furthermore, we discuss the proper understanding of many-valued logics, namely LP and K3 (Kleene strong 3-valued logic), from the perspective of classical logic, along the lines suggested by Susan Haack. We will also discuss some applications of the semantics to issues related to informative contradictions, i.e. contradictions involving quantification over different respects a vague predicate may have, as advanced by Paul \'Egr\'e, and also to the mixed consequence relations, promoted by Pablo Cobreros, Paul \'Egr\'e, David Ripley and Robert van Rooij., Comment: In Proceedings NCL'24, arXiv:2412.20053

A common trait of many machine learning models is that it is often difficult to understand and explain what caused the model to produce the given output. While the explainability of neural networks has been an active field of research in the last years, comparably little is known for quantum machine learning models. Despite a few recent works analyzing some specific aspects of explainability, as of now there is no clear big picture perspective as to what can be expected from quantum learning models in terms of explainability. In this work, we address this issue by identifying promising research avenues in this direction and lining out the expected future results. We additionally propose two explanation methods designed specifically for quantum machine learning models, as first of their kind to the best of our knowledge. Next to our pre-view of the field, we compare both existing and novel methods to explain the predictions of quantum learning models. By studying explainability in quantum machine learning, we can contribute to the sustainable development of the field, preventing trust issues in the future., Comment: 16+16 pages, 3+4 figures

Recently, physics-informed neural networks (PINNs) have emerged as a flexible and promising application of deep learning to partial differential equations in the physical sciences. While offering strong performance and competitive inference speeds on forward and inverse problems, their black-box nature limits interpretability, particularly regarding alignment with expected physical behavior. In the present work, we explore the application of influence functions (IFs) to validate and debug PINNs post-hoc. Specifically, we apply variations of IF-based indicators to gauge the influence of different types of collocation points on the prediction of PINNs applied to a 2D Navier-Stokes fluid flow problem. Our results demonstrate how IFs can be adapted to PINNs to reveal the potential for further studies. The code is publicly available at https://github.com/aleks-krasowski/PINNfluence.

The transition dynamics of two-state systems with time-dependent energy levels, first considered by Landau, Zener, Majorana, and St\"uckelberg, is one of the basic models in quantum physics and has been used to describe various physical systems. We propose here a generalization of the Landau-Zener (LZ) problem characterized by distinct paths of the instantaneous eigenstates as the system evolves in time, while keeping the instantaneous eigenenergies exactly as in the standard LZ model. We show that these paths play an essential role in the transition probability $P$ between the two states, and can lead to superadiabatic transitions, i.e., to a substantial reduction of $P$. As an instructive extreme case, we identify an unconditionally adiabatic regime with $P=0$ no matter how fast the system evolves in time and regardless of the energy gap between the two levels at the anticrossing point. On the other hand, large $P$ occur even in the absence of any anticrossing point. These phenomena can be explained by observing the rotation of the instantaneous eigenvectors on the Bloch sphere. The superadiabatic LZ model can describe valley transition dynamics during charge and spin shuttling in semiconductor quantum dots., Comment: 6 pages, 3 figures

Testing earthquake forecasts is essential to obtain scientific information on forecasting models and sufficient credibility for societal usage. We aim at enhancing the testing phase proposed by the Collaboratory for the Study of Earthquake Predictability (CSEP, Schorlemmer et al., 2018) with new statistical methods supported by mathematical theory. To demonstrate their applicability, we evaluate three short-term forecasting models that were submitted to the CSEP Italy experiment, and two ensemble models thereof. The models produce weekly overlapping forecasts for the expected number of M4+ earthquakes in a collection of grid cells. We compare the models' forecasts using consistent scoring functions for means or expectations, which are widely used and theoretically principled tools for forecast evaluation. We further discuss and demonstrate their connection to CSEP-style earthquake likelihood model testing. Then, using tools from isotonic regression, we investigate forecast reliability and apply score decompositions in terms of calibration and discrimination. Our results show where and how models outperform their competitors and reveal a substantial lack of calibration for various models. The proposed methods also apply to full-distribution (e.g., catalog-based) forecasts, without requiring Poisson distributions or making any other type of parametric assumption.

Philosophers of science commonly connect ontology and science, stating that these disciplines maintain a two-way relationship: on the one hand, we can extract ontology from scientific theories; on the other hand, ontology provides the realistic content of our scientific theories. In this article, we will critically examine the process of naturalizing ontology, i.e., confining the work of ontologists merely to the task of pointing out which entities certain theories commit themselves to. We will use non-relativistic quantum mechanics as a case study. We begin by distinguishing two roles for ontology: the first would be characterized by cataloging existing entities according to quantum mechanics; the second would be characterized by establishing more general ontological categories in which existing entities must be classified. We argue that only the first step is available for a naturalistic approach; the second step not being open for determination or anchoring in science. Finally, we also argue that metaphysics is still a step beyond ontology, not contained in either of the two tasks of ontology, being thus even farther from science., Comment: Forthcoming in THEORIA, Special Issue: "Quantum Mechanics and Reality'', 2024

The valley splitting (VS) of a silicon quantum dot plays an important role for the performance and scalability of silicon spin qubits. In this work we investigate the VS of a SiGe/Si/SiGe heterostructure as a function of the size and location of the silicon quantum dot. We use the effective mass approach to describe a realistic system, which takes into account concentration fluctuations at the Si/SiGe interfaces and also the interface roughness. We predict that the size of the quantum dot is an important parameter for the enhancement of the VS and it can also induce a transition between the disorder-dominated to deterministic-enhanced regimes. Analyzing how the VS changes when we move the quantum dot in a specific direction, we obtain that the size of the quantum dot can be used to reduce the variability of the VS, which is relevant for charge/spin shuttling.

This chapter argues that the general philosophy of science should learn metaphilosophical lessons from the case of metaphysical underdetermination, as it occurs in non-relativistic quantum mechanics. Section 2 presents the traditional discussion of metaphysical underdetermination regarding the individuality and non-individuality of quantum particles. Section 3 discusses three reactions to it found in the literature: eliminativism about individuality; conservatism about individuality; eliminativism about objects. Section 4 wraps it all up with metametaphysical considerations regarding the epistemology of metaphysics of science., Comment: Forthcoming in: Probing the Meaning of Quantum Mechanics. Aerts, D. & Arenhart, J. R. B. & de Ronde, C. & Sergioli, G. (eds.) World Scientific, 2023

Ever since its beginnings, standard quantum mechanics has been associated with a metaphysical view according to which the theory deals with non-individual objects, i.e., objects deprived of individuality in some sense of the term. We shall examine the grounds of the claim according to which quantum mechanics is so closely connected with a metaphysics of non-individuals. In particular, we discuss the attempts to learn the required `metaphysical lessons' required by quantum mechanics coming from four distinct roads: from the formalism of the theory, treating separately the case of the physics and the underlying logic; from the ontology of the theory, understood as the furniture of the world according to the theory; and, at last, we analyze whether a metaphysics of non-individuals is indispensable from a purely metaphysical point of view. We argue that neither non-individuality nor individuality is not to be found imposed on us in any of these levels so that it should be seen as a metaphysical addition to the theory, rather than as a lesson from it., Comment: Forthcoming in J. R. B. Arenhart, R. W. Arroyo (eds.), Non-Reflexive Logics, Non-Individuals, and the Philosophy of Quantum Mechanics: Essays in Honour of the Philosophy of D\'ecio Krause, Springer, Synthese Library 476, https://doi.org/10.1007/978-3-031-31840-5_5

In this work we investigate the transport properties of non-relativistic quantum particles on incommensurate multilayered structures with the thicknesses $w_n$ of the layers following an extended Harper model given by $w_n = w_0 |\cos(\pi a n^{\nu})|$. For the normal incidence case, which means an one-dimensional system, we obtained that for a specific range of energy, it is possible to see a metallic-insulator transition with the exponent $\nu$. A metallic phase is supported for $\nu<1$. We also obtained that for the specific value $\nu=1$ there is an alternation between metallic and insulator phases as we change the disorder strength $w_0$. When we integrate out all incidence angles, which means a two-dimensional system, the metallic-insulator transition can be seen for much larger range of energy compared to the normal incidence case.

The performance and scalability of silicon spin qubits depend directly on the value of the conduction band valley splitting. In this work, we investigate the influence of electromagnetic fields and the interface width on the valley splitting of a quantum dot in a Si/SiGe heterostructure. We propose a new three-dimensional theoretical model within the effective mass theory for the calculation of the valley splitting in such heterostructures that takes into account the concentration fluctuation at the interfaces and the lateral confinement. With this model, we predict that the electric field is an important parameter for valley splitting engineering, since it can shift the probability distribution away from small valley splittings for some interface widths. We also obtain a critical softness of the interfaces in the heterostructure, above which the best option for spin qubits is to consider an interface as wide as possible.

We investigate the propagation of waves in one-dimensional systems with L\'evy-type disorder. We perform a complete analysis of non-relativistic and relativistic wave transmission submitted to potential barriers whose width, separation or both follow L\'evy distributions characterized by an exponent $0 < \alpha <1$. For the first two cases, where one of the parameters is fixed, non-relativistic and relativistic waves present anomalous localization, $\langle T \rangle \propto L^{-\alpha}$. However, for the latter case, in which both parameters follow a L\'evy distribution, non-relativistic and relativistic waves present a transition between anomalous and standard localization as the incidence energy increases relative to the barrier height. Moreover, we obtain the localization diagram delimiting anomalous and standard localization regimes, in terms of incidence angle and energy. Finally, we verify that transmission fluctuations, characterized by its standard deviation, are universal, independent of barrier architecture, wave equation type, incidence energy and angle, further extending earlier studies on electronic localization., Comment: Accepted for publication as a Regular Article in Physical Review E

Traditionally, to be a realist about something means believing in the independent existence of that something. In this line of thought, a scientific realist is someone who believes in the objective existence of the entities postulated by our best scientific theories. In metaphysical terms, what does that mean? In ontological terms, i.e., in terms about what exists, scientific realism can be understood as involving the adoption of an ontology that is scientifically informed. But according to some philosophers, the realistic attitude must go beyond ontology. The way in which this requirement has been understood involves providing a metaphysics for the entities postulated by science, that is, answering questions about the nature of what ontology admits to exist. We discuss how two fashionable approaches face the challenge of providing a metaphysics for science: a form of naturalism and the Viking/Toolbox approach. Finally, we present a third way, which adopts the best of both approaches: the meta-Popperian method, which focuses on discarding the wrong alternatives, or better saying, the metaphysical profiles incompatible with certain theories. We present the meta-Popperian method, a metametaphysical method capable of objectively assessing which metaphysical profiles are incompatible with certain scientific theories. For this, we will use quantum mechanics as a case study, presenting some previously obtained results. As our focus is on methodological questions about the relationship between metaphysics and science; with this method, we can see how science can be used to avoid error in metaphysical issues. In our opinion, this would be a way to develop a productive relationship between science and metaphysics., Comment: In Portuguese. Article accepted for publication in Kriterion, v.63 n.151, 2022. See the final version at

The investigation of curved low-dimensional systems is a topic of great research interest. Such investigations include two-dimensional systems with cylindrical symmetry. In this work, we present a numerical study of the electronic transport properties of metallic nanotubes deviating from the cylindrical form either by having a bump or a depression, and under the influence of a magnetic field. Under these circumstances, it is found that the nanotube may be used as an energy high-pass filter for electrons. It is also shown that the device can be used to tune the angular momentum of transmitted electrons., Comment: The following article has been accepted by J. of Applied Physics

The search for new materials is a very intense task in many technological areas. In 2015, a new variant of graphene was proposed, the pentagraphene, which was followed by the propose of a pentagonal boron nitride structure called penta-BN$_2$. Based on these structures, we investigated the electronic, magnetic, and optical properties of penta-BN$_2$ nanoribbons (p-BNNRs) considering four different kinds of edges, carefully closing the valence shells with H atoms to prevent dangling bonds. To achieve this goal, we used first-principles calculations in a density functional theory framework. Our findings showed that the p-BNNRs have a rich magneto-electronic behavior, varying from semiconductor to half-metal. We obtained that they are ferrimagnetic, having an intrinsic magnetism, which allow potential applications in spintronic or spinwaves. From an optical absorption point of view, they mainly absorb at ultraviolet region of the spectrum, especially at UV-B region, which could indicate a potential application as a UV filter.

We discuss some methodological aspects of the relation between physics and metaphysics by dealing specifically with the case of non-relativistic quantum mechanics. Our main claim is that current attempts to productively integrate quantum mechanics and metaphysics are best seen as approaches of what should be called `the metaphysics of science', which is developed by applying already existing metaphysical concepts to scientific theories. We argue that, in this perspective, metaphysics must be understood as an autonomous discipline. It results that this metaphysics cannot hope to derive any kind of justification from science. Thus, one of the main motivations of such project, which is the obtaining of a scientifically respectable justification for the attribution of a single true metaphysical profile to the posits of a scientific theory, is doomed because of the emergence of metaphysical underdetermination from the outset. If metaphysics floats free from physics, which is a premise of such project of integration between these two areas, then it is always possible to attribute more than one metaphysical profile to dress physical entities., Comment: 19 pages, 1 figure