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W. David Wick

Publications and source records attributed to W. David Wick.

At least 19 recordsLinked to original sources
arXiv2026

Schrodinger Was Right!

Now that we have reached the centennial of Erwin Schrodinger's seminal paper introducing the wavefunction theory of matter, it is right and proper to inquire as to its legacy. It is undeniable that today every paper in atomic physics cites his 1926 equation in the first paragraph. But the philosophy undergirding the wavefunction seems to have fallen into the shadows. And Schrodinger left his program incomplete. I will argue here that recent developments in nonlinear mathematics, including so-called "chaos theory", permit finishing the task. It turns out that one nonlinear addition to his equation from 1926 can resolve both the Measurement Problem and the Randomness Problem. With this emendation, the wavefunction alone suffices to explain the outcomes of many experiments (and it is particles that can be relegated to the shadows).

physics.gen-ph↗
arXiv2025

Islands of Instability in Nonlinear Wavefunction Models in the Continuum: A Different Route to "Chaos"

In two previous papers the author described ``Islands of Instability" that may appear in wavefunction models with nonlinear evolution (of a type proposed originally in the context of the Measurement Problem). Such ``IsoI" represent a new scenario for Hamiltonian systems implying so-called ``chaos". Criteria was derived for, and shown to be fulfilled in, some finite-dimensional (multi-qubit) models, and generalized in the second paper to continuum models. But the only example produced of the latter was a model whose linear Schrodinger equation was exactly-solvable. As exact solutions of many-body problems are rare, here I show that the instability criteria can be verified by plugging test-functions into certain computable expressions, bypassing the solvability blockade. The method can accommodate realistic inter-molecular potentials and so may be relevant to instabilities in fluids and gasses.

quant-ph↗
arXiv2025

Chaos in a Nonlinear Wavefunction Model: An Alternative to Born's Probability Hypothesis

In a prior paper, the author described an instability in a nonlinear wavefunction model. Proposed in connection with the Measurement Problem, the model contained an external potential creating a ``classical'' instability. However, it is interesting to ask whether such models possess an intrinsic randomness -- even ``chaos" -- independent of external potentials. In this work, I investigate the criterion analytically and simulate from a small (``3 qubit") model, demonstrating that the Lyapunov exponent -- a standard measure of ``chaos" -- is positive. I also extend the instability criterion to models in the continuum. These results suggest that the boundary between classical and wavefunction physics may also constitute the threshold of chaos, and present an alternative to Max Born's ad hoc probability hypothesis: random outcomes in experiments result not from ``wave-particle duality" or ``the existence of the quantum," but from sensitive dependence on initial conditions, as is common in the other sciences.

quant-ph↗
arXiv2025

Can Schroedingerist Wavefunction Physics Explain Brownian Motion? III: A One-Dimensional Heavy and Light Particles Model Exhibiting Brownian-Motion-Like Trajectories and Diffusion

In two prior papers of this series, it was proposed that a wavefunction model of a heavy particle and a collection of light particles might generate ``Brownian-Motion-Like" trajectories as well as diffusive motion (displacement proportional to the square-root of time) of the heavy particle, but did not exhibit a concrete instance. Here we introduce a one-space-dimensional model which, granted a finite perturbation series, fulfills the criteria for BML trajectories and diffusion. We note that Planck's constant and the molecular mass of light particles make an appearance in the diffusion coefficient, which further differentiates the present theory from the work of Poincar{é} and Einstein in the previous century.

quant-ph↗
arXiv2025

Locality, Micro- vs. Macro-, Particle Interpretations and All That: A Lagrangian Approach to the Measurement Problem

In 2017, this author proposed, as a resolution of the Measurement Problem, that terms be added to Schrodinger's wavefunction equation, rendering it nonlinear. Said equation derived from a trick employed by S. Weinberg in 1989 which may be unfamiliar to most physicists, as well as uninterpretable in terms of local ("particle") interactions. Motivated by A. O. Barut's work on electrodynamics, here I analyze which kinds of nonlinear theories can be derived from Lagrangian field-theory by integrating out some fields. The issues of "What is a local interaction?" and "Might there be Micro- and Macro-fields?" arise. In the end, I will argue that my 2017 theory cannot be given a "particle" interpretation, nor be derived from a splitting into the two categories of fields.

quant-ph↗
arXiv2025

Can the Infamous Boundary Be Found in Macromolecules? Also, von Neumann vs. Schroedinger ensembles, and `Hund's Paradox' in quantum chemistry

John Bell coined the phrase ``Infamous Boundary" for the point where classical physics splits off from quantum physics. Many authors, including the present one, have advanced theories with the intention of defining and locating this ``shifty split"; most propose that it lies somewhere on the scale of apparatus. But what if it resides at the level of macromolecules? I show here that this question is intimately connected to the choice of thermal ensembles and to the so-called `Hund's Paradox' in quantum chemistry. I propose an experimental set-up that could in principle reveal the IB lurking in asymmetric macromolecules.

quant-ph↗
arXiv2025

Nonlinear Nonlocal: Comparing A. O. Barut's Theory to Mine with special emphasis on That Dot on the Screen

In the 1980's and 90's, A. O Barut and colleagues developed a nonperturbative approach to electrodynamics eschewing so-called ``second-quantization". Based on incorporation of self-energy terms, the resulting nonlinear and nonlocal theory explained many well-known phenomena of atomic and radiation physics. In 2017, this author introduced a nonlinear, nonlocal theory with the intent of resolving the Measurement Problem. Barut also suggested that his theory resolved such paradoxes. Here I compare the two theories with special attention to That Dot on the Screen.

quant-ph↗
arXiv2025

That Dot on the Screen: also, what about Born? and other objections to wavefunction physics

In this paper I address the most common objections to the claim that Schrodinger was right in 1926: the wavefunction provides the correct, and complete, description of atomic phenomena. I suggest that the line of droplets in the Wilson cloud chamber, the click of the ``photon detector", and ``that dot on the screen" can all be explained within a context of wavefunction models and Schrodinger's-type equations, albeit nonlinear. No auxiliary hypotheses about point particles or probabilities are required. The random locations of the triggered ``particle detectors" can be explained by ``chaos" (meaning sensitive dependence on initial conditions). Even Born's ad hoc invocation of probabilities may be justifiable in certain circumstances. As an illustration, I present simulations from a (toy) wavefunction ``particle-detectors" model.

physics.gen-ph↗
arXiv2024

On Schrödingerist Quantum Thermodynamics

From the point of view of Schrödingerism, a wavefunction-only philosophy, thermodynamics must be recast in terms of an ensemble of wavefunctions, rather than classical particle configurations or "found" values of Copenaghen Quantum Mechanics. Recapitulating the historical sequence, we consider here several models of magnets that classically can exhibit a phase transition to a low-temperature magnetized state. We formulate wavefunction analogues including a "Schrödingerist QUantum Ising Model" (SQUIM), a "Schrödingerist Curie-Weiss Model"(SCWM), and others. We show that the SQUIM with free boundary conditions and distinguishable "spins" has no finite-temperature phase transition, which we attribute to entropy swamping energy. The SCWM likewise, even assuming exchange symmetry in the wavefunction (in this case the analytical argument is not totally satisfactory and we helped ourself with a computer analysis). But a variant model with "Wavefunction Energy" (introduced in prior communications about Schrödingerism and the Measurement Problem) does have a phase transition to a magnetised state. The three results together suggest that magnetization in large wavefunction spin chains appears if and only if we consider indistinguishable particles and block macroscopic dispersion (i.e. macroscopic superpositions) by energy conservation. Our principle technique involves transforming the problem to one in probability theory, then applying results from Large Deviations, particularly the Gärtner-Ellis Theorem. Finally, we discuss Gibbs vs. Boltzmann/Einstein entropy in the choice of the quantum thermodynamic ensemble, as well as open problems. PhySH: quantum theory, quantum statistical mechanics, large deviation & rare event statistics. https://github.com/leodecarlo/Computing-Large-Deviation-Functionals-of-not-identically-distributed-independent-random-variables

quant-ph↗
arXiv2023

Can Schrodingerist Wavefunction Physics Explain Brownian Motion? II. The Diffusion Coefficient

In the first paper of this series, I investigated whether a wavefunction model of a heavy particle and a collection of light particles might generate "Brownian-Motion-Like" trajectories of the heavy particle. I concluded that it was possible, but left unsettled the second claim in Einstein's classical program: diffusive motion, proportional to the square-root of time, as opposed to ballistic motion, proportional to the time. In this paper, I derive a criterion for diffusive motion, as well as an expression for the diffusion coefficient. Unfortunately, as in paper I, no exact solutions are available for the models, making checking the criterion difficult. But a virtue of the method employed here is that, given adequate information about model eigenvalues and eigenfunctions, diffusion can be definitively ruled in or out.

quant-ph↗
arXiv2023

Can Schroedingerist Wavefunction Physics Explain Brownian Motion?

Einstein's 1905 analysis of the Brownian Motion of a pollen grain in a water droplet as due to statistical variations in the collisions of water molecules with the grain, followed up by Perrin's experiments, provided one of the most convincing demonstrations of the reality of atoms. But in 1926 Schroedinger replaced classical particles by wavefunctions, which cannot undergo collisions. Can a Schroedingerist wavefunction physics account for Perrin's observations? As systems confined to a finite box can only generate quasiperiodic signals, this seems impossible, but I argue here that the issue is more subtle. I then introduce several models of the droplet-plus-grain; unfortunately, no explicit solutions are available (related is the remarkable fact that the harmonics of a general right triangle are still unknown). But from generic features of the models I conclude that: (a) wavefunction models may generate trajectories resembling those of a stochastic process; (b) diffusive behavior may appear for a restricted time interval; and (c) additional ``Wave Function Energy", by restricting ``cat" formation, can render the observations more ``classical". But completing the Einstein program of linking diffusion to viscosity and temperature in wavefunction models is still challenging.

quant-ph↗
arXiv2020

On Non-Linear Quantum Mechanics, Space-Time Wavefunctions, and Compatibility with General Relativity

In previous papers I expounded non-linear Schrodingerist quantum mechanics as a solution of the Measurement Problem. Here I show that NLQM is compatible with Einstein's theory of General Relativity. The extension to curved space-times presumes adoption of "space-time wavefunctions" (sometimes called "multi-time wavefunctions") and some additional algebraic structure: a "bitensor" supplementing Einstein's metric tensor. This kind of matter may violate the Strong Energy Condition even without a mass term, possibly with implications for the formation of singularities within Black Holes.

quant-ph↗
arXiv2018

On Non-Linear Quantum Mechanics and the Measurement Problem III. Poincare Probability and ... Chaos?

Paper I of this series introduced a nonlinear version of quantum mechanics that blocks cats, and paper II postulated a random part of the wavefunction to explain outcomes in experiments such as Stern-Gerlach or EPRB. However, an ad hoc extra parameter was assumed for the randomness. Here I provide some analytic and simulation evidence that the nonlinear theory exhibits sensitive dependence on initial conditions in measurement scenarios, perhaps implying that the magnitude of randomness required is determined by structural features of the model, and does not require a free parameter.

quant-ph↗
arXiv2017

On Non-Linear Quantum Mechanics and the Measurement Problem II. The Random Part of the Wavefunction

In the first paper of this series, I introduced a non-linear, Hamiltonian, generalization of Schroedinger's theory that blocks formation of macroscopic dispersion ("cats"). But that theory was entirely deterministic, and so the origin of random outcomes in experiments such as Stern-Gerlach or EPRB was left open. Here I propose that Schroedinger's wavefunction has a random component and demonstrate that such an improvised stochastic theory can violate Bell's inequality. Repeated measurements and the back-reaction on the microsystem are discussed in a toy example. Experiments that might falsify the theory are described.

quant-ph↗
arXiv2017

On Non-linear Quantum Mechanics and the Measurement Problem I. Blocking Cats

Working entirely within the Schroedinger paradigm, meaning wavefunction only, I present a modification of his theory that prevents formation of macroscopic dispersion (MD; "cats"). The proposal is to modify the Hamiltonian based on a method introduced by Steven Weinberg in 1989, as part of a program to test quantum mechanics at the atomic or nuclear level. By contrast, the intent here is to eliminate MD without affecting the predictions of quantum mechanics at the microscopic scale. This restores classical physics at the macro level. Possible experimental tests are indicated and the differences from previous theories discussed. In a second paper, I will address the other difficulty of wavefunction physics without the statistical (Copenhagen) interpretation: how to explain random outcomes in experiments such as Stern-Gerlach, and whether a Schroedingerist theory with a random component can violate Bell's inequality.

quant-ph↗
arXiv2014

Stopping the SuperSpreader Epidemic, Part III: Prediction

In two previous papers, I introduced SuperSpreader (SS) epidemic models, offered some theoretical discussion of prevention issues, and fitted some models to data derived from published accounts of the ongoing MERS epidemic (concluding that a pandemic is likely). Continuing on this theme, here I discuss prediction: whether, in a disease outbreak driven by superspreader events, a rigorous decision point---meaning a declaration that a pandemic is imminent---can be defined. I show that all sources of prediction bias contribute to generating false negatives (i.e., discounting the chance of a pandemic when it is looming or has already started). Nevertheless, the statistical difficulties can be overcome by improved data gathering and use of known techniques that decrease bias. One peculiarity of the SS epidemic is that the prediction can sometimes be made long before the actual pandemic onset, generating lead time to alert the medical community and the public. Thus modeling is useful to overcome a false sense of security arising from the long "kindling times" characteristic of SS epidemics and certain political/psychological factors, as well as improve the public health response.

q-bio.PE↗
arXiv2014

Stopping the SuperSpreader Epidemic, Part II: MERS Goes Pandemic

In a paper of August 2013, I discussed the so-called SuperSpreader (SS) epidemic model and emphasized that it has dynamics differing greatly from the more-familiar uniform (or Poisson) textbook model. In that paper, SARS in 2003 was the representative instance and it was suggested that MERS may be another. In April 2014, MERS incident cases showed a spectacular spike (going from a handful in the previous April to more than 260 in that month of 2014) reminiscent of a figure I published nine months earlier. Here I refit the two-level and several variant SS models to incident data from January 1, 2013--April 30, 2014 and conclude that MERS will go pandemic (all other factors remaining the same). In addition, I discuss a number of model-realism and fitting methodology issues relevant to analysing SS epidemics.

q-bio.PE↗