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Some authors have argued that spacetime in general relativity should be given a radically different interpretation from the ones given to spacetime in other theories in virtue of it being a gauge theory. In this article I review this sort of argument and argue against this view. That is, I argue that spacetime in general relativity can be understood analogously to spacetime in other models and that the argument from the diffeomorphism invariance of the theory misapplies the concepts of gauge theory to a context in which they are of limited application.

In this paper we approach the problem of superdeterminism from a novel point of view, highlighting its character as a more metaphysical than scientific proposition. First, we introduce a distinction between two types of superdeterministic theories, naïve (NSD) and metaphysical (MSD), and argue how NSD presents significant epistemic flaws. We show how NSD justifies itself through claims to fundamentality, thus connoting itself as a metaphysical theory rather than a scientific one. We finally illustrate that the most developed MSD model so far, Invariant Set Theory, implicitly proposes a confused form of priority monism. Our paper thus reinforces the thesis that theories should demonstrate rather than assume fundamentality and that it is methodologically flawed for a theory to assume its own fundamentality for the sole purpose of defending against criticisms.

Methods of selecting samples from larger populations may produce bias, in either direction: inducing correlations between variables independent in the full population, or masking correlations between variables dependent in the full population. Here we propose a surprising application of these familiar ideas. We argue that they are relevant to puzzling correlations uncovered in quantum theory by John Stewart Bell (Bell 1964). In the light of Bell's work and subsequent experiments it is widely believed that the quantum world is 'nonlocal', in apparent tension with relativity. Many hold that the only alternative is to abandon 'realism', the view that there is an objective world independent of measurement. We propose instead that Bell's correlations are selection artefacts, in tension neither with relativity nor realism. In standard two-particle Bell experiments the relevant selection is a preselection, achieved by the preparation of the initial state. Again, selection bias via preselection is familiar elsewhere in science, but it doesn't seem to have been noticed that it is applicable in this case.

Conceptual surveys of multiple choice format have been developed to test the effect of pedagogical interventions on students understanding of physics knowledge. Predominantly, they are administered in pre and posttest settings and analyzed to obtain a performance gain. However, focusing on the correct answers to each question alone ignores the incorrect options which could inform us the stability and coherency of the knowledge structure of students. According to the resource model framework, each specific answer from students could reflect a specific cognitive resource being activated and implemented in the context at hand. Consequently, conceptual surveys could demonstrate how instruction could affect the activation of different cognitive resources of students in a variety of contexts when administered before and after instruction. Guided by the resources framework, we propose a transition matrix analysis to analyze data collected through conceptual surveys to investigate how instruction affects the consistency of cognitive resources activation by students. To provide proof of concept, we demonstrated how to utilize this method by analyzing students responses to a subset of questions from the DIRECT survey in a classroom study.

We present a derivation at a level suitable for undergraduates of the Ostrogradsky formalism for Lagrangians in classical mechanics that depend upon an arbitrary number of time derivatives of the configuration. From the boundary term in the first variation of the Lagrangian we derive the Ostrogradsky formulas that define the Hamiltonian formulation of mechanical systems. Worked examples, exercises, and applications to the literature are also provided. An accompanying computer program that implements the formalism is discussed in the Supplementary Materials, and code for computing Hamiltonians via the Ostrogradsky formalism is provided in the Supplementary Materials and in a GitHub repository.

Gravitational lensing is often introduced through the bending of light by mass, but its geometrical nature can be difficult to visualize without invoking the full machinery of general relativity. We present a geometrical-optics analogy in which selected lensing-like image morphologies are generated by ray tracing through axicon-type lenses. In contrast with analogies based on a spatially varying refractive index, the present model uses optical elements with a constant refractive index; the redistribution of rays is produced by the geometry of the refracting surfaces. After deriving the ray-tracing equations for a general two-surface axicon, we apply the model to conical and exponential profiles. Axially symmetric configurations generate ring-like images, misaligned incidence produces partial arcs, and broken axial symmetry leads to four-image patterns reminiscent of an Einstein cross. The model is not intended as a physical substitute for a relativistic lens equation, but as a computational and pedagogical tool for exploring how surface geometry and symmetry control ray deflection, redistribution, and image multiplicity.

In Newtonian fluids, impact of a droplet on a liquid pool births a cavity, crown, capillary waves, and Worthington jet. The corresponding hydrodynamic events for elastic or Boger fluids, however, remain an uncharted domain of comprehension and exploration. We thoroughly investigate, via experiments, theory, and simulations, how elastic energy storage, fluid relaxation, and competitive inertio elasto capillarity govern the spatio temporal evolution of the cavity, the crown, and the ensuing Worthington jet in polymeric elastic fluids. The events are systematically explored over a wide range of impact Weber and Deborah numbers, considering varied Newtonian and elastic fluid droplet pool combinations, and revealing new, and distinct morphological regimes compared to Newtonian counterparts. We illustrate that these new findings are purely driven by fluid elasticity, and not by viscosity or interfacial tension. We derive a theory for cavity radius evolution, using energy conservation within potential-flow framework. We show that 30-40 % of the droplets kinetic impact energy may be stored as elastic energy by the stretching polymer chains during cavity expansion. Appealing to the FENE P model, we derive a theory for the temporal evolution of the radius of the elongated Worthington jet. We show that in elasto capillary regime, competitive elastic and capillary stresses lead to exponential decay of the jet radius. The role of elastic stresses and the local velocity field in governing cavity evolution, morphology, and jet formation are further elucidated through computer simulations. Our findings significantly advance the uncharted paradigm of interplay between inertia, capillarity, and elasticity in droplet-pool interaction elastohydrodynamics.

Quantum computing promises transformative advances across science and industry, yet the physical hardware that enables these computations remains invisible to the public: quantum processors operate inside sealed dilution refrigerators at temperatures near absolute zero, making direct observation impossible. This "imagination gap" between quantum computing's growing societal impact and the public's ability to visualize it represents a significant barrier to quantum literacy and workforce development. We present Quantum Cinema, an open-source, browser-based interactive application that closes this gap by transforming invisible quantum hardware into explorable, cinematic experiences using generative world models. Quantum Cinema guides users through a four-act narrative – from the foundational Nobel Prize-winning science of quantum entanglement, through curated video introductions to three major quantum computing architectures (trapped-ion, neutral-atom, and superconducting systems), into immersive three-dimensional generative worlds that make invisible quantum phenomena observable, and finally to interactive radar-chart comparisons grounded in real quantum device specifications. All three-dimensional environments are generated using WorldLabs' generative world model platform and are scientifically grounded in curated metrics from Amazon Web Services (AWS) Braket quantum hardware. Quantum Cinema requires no installation, no specialized hardware, and no quantum computing background. It is designed to serve two distinct communities: scholars and developers seeking to replicate or extend the platform, and educators, researchers, and science communicators seeking an intuitive tool for explaining quantum hardware to diverse audiences. This paper describes the system architecture, the generative world model pipeline, use cases for both communities, and directions for future work.