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Timothy McDevitt

Publications and source records attributed to Timothy McDevitt.

15 recordsLinked to original sources
arXiv2026

Quantum Reconstruction and Phenomenology per the Relativity Principle

We use the relativity principle to complete axiomatic reconstructions of quantum mechanics (QM) via information-theoretic principles that are based on Darrigol's "discreteness" requirement or its equivalent, e.g., Brukner & Zeilinger's Information Invariance & Continuity or Khrennikov's quantum action invariance principle. In this approach to the quantum reconstruction program (QRP), the Hilbert space kinematics of QM is derived most fundamentally from the experimentally motivated postulate of "discreteness," rendering QM a principle theory as defined by Einstein. Special relativity is also a principle theory, since its Lorentz transformation kinematics is derived from the experimentally motivated light postulate. While special relativity has a compelling fundamental principle (relativity principle) to account for its experimentally motivated light postulate, QRP has not produced a compelling fundamental principle to account for its experimentally motivated "discreteness" requirement. We complete QRP by showing how the "discreteness" requirement is necessitated by the relativity principle and Planck's radiation law, just like the light postulate is necessitated by the relativity principle and Maxwell's equations. Accordingly, the fundamental explanans for time dilation, length contraction, quantum superposition, and entanglement is the relativity principle. Phenomenologically speaking, the relativity principle is "the equality of all perspectives." Thus, quantum entanglement isn't evidence for the violation of intersubjective agreement or the need to abandon factive or objective models of reality, as in relational interpretations of QM. It is evidence that reality is not a fragmented collage of different subjective experiences from different perspectives, it's a comprehensive and coherent integration of those different subjective experiences per the equality of all perspectives.

quant-ph↗
arXiv2024

Completing the Quantum Reconstruction Program via the Relativity Principle

We explain how the disparate kinematics of quantum mechanics (finite-dimensional Hilbert space of QM) and special relativity (Minkowski spacetime from the Lorentz transformations of SR) can both be based on one principle (relativity principle). This is made possible by the axiomatic reconstruction of QM via information-theoretic principles, which has successfully recast QM as a principle theory a la SR. That is, in the quantum reconstruction program (QRP) and SR, the formalisms (Hilbert space and Lorentz transformations, respectively) are derived from empirically discovered facts (Information Invariance & Continuity and light postulate, respectively), so QM and SR are "principle theories" as defined by Einstein. While SR has a compelling fundamental principle to justify its empirically discovered fact (relativity principle), QRP has not produced a compelling fundamental principle or causal mechanism to account for its empirically discovered fact. To unify these disparate kinematics, we show how the relativity principle ("no preferred reference frame" NPRF) can also be used to justify Information Invariance & Continuity. We do this by showing that when QRP's operational notion of measurement is spatialized, Information Invariance & Continuity entails the empirically discovered fact that everyone measures the same value for Planck's constant h, regardless of their relative spatial orientations or locations (Planck postulate). Since Poincare transformations relate inertial reference frames via spatial rotations and translations as well as boosts, the relativity principle justifies the Planck postulate just like it justifies the light postulate. Essentially, NPRF + c is an adynamical global constraint over the spacetime configuration of worldtubes for bodily objects while NPRF + h is an adynamical global constraint over the distribution of quanta among those bodily objects.

quant-ph↗
arXiv2021

"Mysteries" of Modern Physics and the Fundamental Constants $c$, $h$, and $G$

We review how the kinematic structures of special relativity and quantum mechanics both stem from the relativity principle, i.e., "no preferred reference frame" (NPRF). Essentially, NPRF applied to the measurement of the speed of light $c$ gives the light postulate and leads to the geometry of Minkowski spacetime, while NPRF applied to the measurement of Planck's constant $h$ gives "average-only" projection and leads to the denumerable-dimensional Hilbert space of quantum mechanics. These kinematic structures contain the counterintuitive aspects ("mysteries") of time dilation, length contraction, and quantum entanglement. In this essay, we extend the application of NPRF to the gravitational constant $G$ and show that it leads to the "mystery" of the contextuality of mass in general relativity. Thus, we see an underlying coherence and integrity in modern physics via its "mysteries" and the fundamental constants $c$, $h$, and $G$.

quant-ph↗
arXiv2021

The Relativity Principle at the Foundation of Quantum Mechanics

Quantum information theorists have created axiomatic reconstructions of quantum mechanics (QM) that are very successful at identifying precisely what distinguishes quantum probability theory from classical and more general probability theories in terms of information-theoretic principles. Herein, we show how one such principle, Information Invariance & Continuity, at the foundation of those axiomatic reconstructions maps to "no preferred reference frame" (NPRF, aka "the relativity principle") as it pertains to the invariant measurement of Planck's constant h for Stern-Gerlach (SG) spin measurements. This is in exact analogy to the relativity principle as it pertains to the invariant measurement of the speed of light c at the foundation of special relativity (SR). Essentially, quantum information theorists have extended Einstein's use of NPRF from the boost invariance of measurements of c to include the SO(3) invariance of measurements of h between different reference frames of mutually complementary spin measurements via the principle of Information Invariance & Continuity. Consequently, the "mystery" of the Bell states that is responsible for the Tsirelson bound and the exclusion of the no-signalling, "superquantum" Popescu-Rohrlich joint probabilities is understood to result from conservation per Information Invariance & Continuity between different reference frames of mutually complementary qubit measurements, and this maps to conservation per NPRF in spacetime. If one falsely conflates the relativity principle with the classical theory of SR, then it may seem impossible that the relativity principle resides at the foundation of non-relativisitic QM. In fact, there is nothing inherently classical or quantum about NPRF. Thus, the axiomatic reconstructions of QM have succeeded in producing a principle account of QM that reveals as much about Nature as the postulates of SR.

quant-ph↗
arXiv2021

Introducing Quantum Entanglement to First-Year Students: Resolving the Trilemma

While quantum mechanics (QM) is covered at length in introductory physics textbooks, the concept of quantum entanglement is typically not covered at all, despite its importance in the rapidly growing area of quantum information science and its extensive experimental confirmation. Thus, physics educators are left to their own devices as to how to introduce this important concept. Regardless of how a physics educator chooses to introduce quantum entanglement, they face a trilemma involving its mysterious Bell-inequality-violating correlations. They can compromise on the the completeness of their introduction and simply choose not to share that fact, totally ignoring the 2022 Nobel Prize in Physics. They can frustrate their more curious students by introducing the mystery and simply telling them that the QM formalism with its associated (equally mysterious) conservation law maps beautifully to the experiments, so there is nothing else that needs to be said. Or, they can compromise the rigor of their presentation and attempt to resolve the mystery by venturing into the metaphysical quagmire of competing QM interpretations. Herein, we resolve this trilemma in precisely the same way that Einstein resolved the mysteries of time dilation and length contraction that existed in the late nineteenth century. That is, we resort to "principle" explanation based on the mathematical consequences of "empirically discovered" facts. Indeed, our principle account of quantum entanglement is even based on the same principle Einstein used, i.e., the relativity principle or "no preferred reference frame." Thus, this principle resolution of the trilemma is as complete, satisfying, analytically rigorous, and accessible as the standard introduction of special relativity for first-year physics students.

physics.ed-ph↗
arXiv2018

Answering Mermin's Challenge with Conservation per No Preferred Reference Frame

In 1981, Mermin published a now famous paper titled, "Bringing home the atomic world: Quantum mysteries for anybody" that Feynman called, "One of the most beautiful papers in physics that I know." Therein, he presented the "Mermin device" that illustrates the conundrum of quantum entanglement per the Bell spin states for the "general reader." He then challenged the "physicist reader" to explain the way the device works "in terms meaningful to a general reader struggling with the dilemma raised by the device." Herein, we show how "conservation per no preferred reference frame (NPRF)" answers that challenge. In short, the explicit conservation that obtains for Alice and Bob's Stern-Gerlach spin measurement outcomes in the same reference frame holds only on average in different reference frames, not on a trial-by-trial basis. This conservation is SO(3) invariant in the relevant symmetry plane in real space per the SU(2) invariance of its corresponding Bell spin state in Hilbert space. Since NPRF is also responsible for the postulates of special relativity, and therefore its counterintuitive aspects of time dilation and length contraction, we see that the symmetry group relating non-relativistic quantum mechanics and special relativity via their "mysteries" is the restricted Lorentz group.

quant-ph↗
arXiv2018

Why the Tsirelson Bound? Bub's Question and Fuchs' Desideratum

To answer Wheeler's question "Why the quantum?" via quantum information theory according to Bub, one must explain both why the world is quantum rather than classical and why the world is quantum rather than superquantum, i.e., "Why the Tsirelson bound?" We show that the quantum correlations and quantum states corresponding to the Bell basis states, which uniquely produce the Tsirelson bound for the Clauser-Horne-Shimony-Holt quantity, can be derived from conservation per no preferred reference frame (NPRF). A reference frame in this context is defined by a measurement configuration, just as with the light postulate of special relativity. We therefore argue that the Tsirelson bound is ultimately based on NPRF just as the postulates of special relativity. This constraint-based/principle answer to Bub's question addresses Fuchs' desideratum that we "take the structure of quantum theory and change it from this very overt mathematical speak ... into something like [special relativity]." Thus, the answer to Bub's question per Fuchs' desideratum is, "the Tsirelson bound obtains due to conservation per NPRF."

quant-ph↗
arXiv2016

End of a Dark Age?

We argue that dark matter and dark energy phenomena associated with galactic rotation curves, X-ray cluster mass profiles, and type Ia supernova data can be accounted for via small corrections to idealized general relativistic spacetime geometries due to disordered locality. Accordingly, we fit THINGS rotation curve data rivaling modified Newtonian dynamics, ROSAT/ASCA X-ray cluster mass profile data rivaling metric-skew-tensor gravity, and SCP Union2.1 SN Ia data rivaling $\Lambda$CDM without non-baryonic dark matter or a cosmological constant. In the case of dark matter, we geometrically modify proper mass interior to the Schwarzschild solution. In the case of dark energy, we modify proper distance in Einstein-deSitter cosmology. Therefore, the phenomena of dark matter and dark energy may be chimeras created by an errant belief that spacetime is a differentiable manifold rather than a disordered graph.

physics.gen-ph↗
arXiv2015

The Missing Mass Problem as a Manifestation of GR Contextuality

In Newtonian gravity, mass is an intrinsic property of matter while in general relativity (GR), mass is a contextual property of matter, i.e., matter can simultaneously possess two different values of mass when it is responsible for two different spatiotemporal geometries. Herein, we explore the possibility that the astrophysical missing mass attributed to non-baryonic dark matter (DM) actually obtains because we have been assuming the Newtonian view of mass rather than the GR view. Since an exact GR solution for realistic astrophysical situations is not feasible, we explore GR-motivated ansatzes relating proper mass and dynamic mass for one and the same baryonic matter, as justified by GR contextuality. We consider four GR alternatives and find that the GR ansatz motivated by metric perturbation theory works well in fitting galactic rotation curves (THINGS data), the mass profiles of X-ray clusters (ROSAT and ASCA data) and the angular power spectrum of the cosmic microwave background (CMB, Planck 2015 data) without DM. We compare our galactic rotation curve fits to modified Newtonian dynamics (MOND), Burkett halo DM and Navarro-Frenk-White (NFW) halo DM. We compare our X-ray cluster mass profile fits to metric skew-tensor gravity (MSTG) and core-modified NFW DM. We compare our CMB angular power spectrum fit to scalar-tensor-vector gravity (STVG) and $\Lambda$CDM. Overall, we find our fits to be comparable to those of MOND, MSTG, STVG, $\Lambda$CDM, Burkett, and NFW. We present and discuss correlations and trends for the best fit values of our fitting parameters. For the most part, the correlations are consistent with well-established results at all scales, which is perhaps surprising given the simple functional form of the GR ansatz.

physics.gen-ph↗
arXiv2014

Concerning Quadratic Interaction in the Quantum Cheshire Cat Experiment

In a July 2014 Nature Communications paper, Denkmayr et al. claim to have instantiated the so-called quantum Cheshire Cat experiment using neutron interferometry. Crucial to this claim are the weak values which must imply the quantum Cheshire Cat interpretation, i.e., "the neutron and its spin are spatially separated" in their experiment. While they measured the correct weak values for the quantum Cheshire Cat interpretation, the corresponding implications do not obtain because, as we show, those weak values were measured with both a quadratic and a linear magnetic field Bz interaction. We show explicitly how those weak values imply quantum Cheshire Cat if the Bz interaction is linear and then we show how the quadratic Bz interaction destroys the quantum Cheshire Cat implications of those weak values. Since both linear and quadratic Bz interactions contribute equally to the neutron intensity in this experiment, the deviant weak value implications are unavoidable. Because weak values were used successfully to compute neutron intensities for weak Bz in this experiment, it is clearly the case that one cannot make ontological inferences from weak values without taking into account the corresponding interaction strength.

quant-ph↗
arXiv2011

Being, Becoming and the Undivided Universe: A Dialogue between Relational Blockworld and the Implicate Order Concerning the Unification of Relativity and Quantum Theory

In this paper two different approaches to unification will be compared, Relational Blockworld (RBW) and Hiley's implicate order. Both approaches are monistic in that they attempt to derive matter and spacetime geometry 'at once' in an interdependent and background independent fashion from something underneath both quantum theory and relativity. Hiley's monism resides in the implicate order via Clifford algebras and is based on process as fundamental while RBW's monism resides in spacetimematter via path integrals over graphs whereby space, time and matter are co-constructed per a global constraint equation. RBW's monism therefore resides in being (relational blockworld) while that of Hiley's resides in becoming (elementary processes). Regarding the derivation of quantum theory and relativity, the promises and pitfalls of both approaches will be elaborated. Finally, special attention will be paid as to how Hiley's process account might avoid the blockworld implications of relativity and the frozen time problem of canonical quantum gravity.

quant-ph↗
arXiv2011

Gauge Invariance from a Graphical Self-Consistency Criterion

We propose that quantum physics is the continuous approximation of a more fundamental, discrete graph theory (theory X). Accordingly, the Euclidean transition amplitude Z provides a partition function for geometries over the graph, which is characterized topologically by the difference matrix and source vector of the discrete graphical action. The difference matrix and source vector of theory X are related via a graphical self-consistency criterion (SCC) based on the boundary of a boundary principle on a graph. In this approach, the SCC ensures the source vector is divergence-free and resides in the row space of the difference matrix. Accordingly, the difference matrix will necessarily have a nontrivial eigenvector with eigenvalue zero, so the graphical SCC is the origin of gauge invariance. Factors of infinity associated with gauge groups of infinite volume are excluded in our approach, since Z is restricted to the row space of the difference matrix and source vector. Using this formalism, we obtain the two-source Euclidean transition amplitude over a (1+1)- dimensional graph with N vertices fundamental to the scalar Gaussian theory.

quant-ph↗
arXiv2009

An Adynamical, Graphical Approach to Quantum Gravity and Unification

We use graphical field gradients in an adynamical, background independent fashion to propose a new approach to quantum gravity and unification. Our proposed reconciliation of general relativity and quantum field theory is based on a modification of their graphical instantiations, i.e., Regge calculus and lattice gauge theory, respectively, which we assume are fundamental to their continuum counterparts. Accordingly, the fundamental structure is a graphical amalgam of space, time, and sources (in parlance of quantum field theory) called a "spacetimesource element." These are fundamental elements of space, time, and sources, not source elements in space and time. The transition amplitude for a spacetimesource element is computed using a path integral with discrete graphical action. The action for a spacetimesource element is constructed from a difference matrix K and source vector J on the graph, as in lattice gauge theory. K is constructed from graphical field gradients so that it contains a non-trivial null space and J is then restricted to the row space of K, so that it is divergence-free and represents a conserved exchange of energy-momentum. This construct of K and J represents an adynamical global constraint between sources, the spacetime metric, and the energy-momentum content of the element, rather than a dynamical law for time-evolved entities. We use this approach via modified Regge calculus to correct proper distance in the Einstein-deSitter cosmology model yielding a fit of the Union2 Compilation supernova data that matches LambdaCDM without having to invoke accelerating expansion or dark energy. A similar modification to lattice gauge theory results in an adynamical account of quantum interference.

quant-ph↗
arXiv2009

Relational Blockworld: Towards a Discrete Graph Theoretic Foundation of Quantum Mechanics

We propose a discrete path integral formalism over graphs fundamental to quantum mechanics (QM) based on our interpretation of QM called Relational Blockworld (RBW). In our approach, the transition amplitude is not viewed as a sum over all field configurations, but is a mathematical machine for measuring the symmetry of the discrete differential operator and source vector of the discrete action. Therefore, we restrict the path integral to the row space of the discrete differential operator, which also contains the discrete source vector, in order to avoid singularities. In this fashion we obtain the two-source transition amplitude over a "ladder" graph with N vertices. We interpret this solution in the context of the twin-slit experiment.

quant-ph↗