Dustin Lazarovici

Technion - Israel Institute of Technology | technion

A longstanding issue in the Everettian (Many-Worlds) interpretation is to justify and make sense of the Born rule that underlies the statistical predictions of standard quantum mechanics. The paper offers a reappraisal of Everett’s original account in light of the recent literature on the concept of typicality. It argues that Everett’s derivation o...

Bohmian mechanics grounds the predictions of quantum mechanics in precise dynamical laws for a primitive ontology of point particles. In an appraisal of the de-Broglie-Bohm theory, the paper discusses the crucial epistemological and conceptual role that a primitive ontology plays within a physical theory. It argues that quantum theories without pri...

Bohmian mechanics grounds the predictions of quantum mechanics in precise dynamical laws for a primitive ontology of point particles. In an appraisal of the de-Broglie–Bohm theory, the paper discusses the crucial epistemological and conceptual role that a primitive ontology plays within a physical theory. It argues that quantum theories without pri...

As mentioned in Chap. 2, different quantum theories without observers have been suggested and we shall present one now which is particularly well worked out: Bohmian mechanics—a quantum theory of particles in motion.

This will be a very hard chapter. Not because of abstract and technically advanced mathematics, which can easily be learned as soon as the underlying physics is clear, that is, as soon as the need for abstraction is evident. It will be hard for two reasons. First, there does not exist a fundamental, mathematically coherent and consistent formulatio...

What has been said so far is all well and good, but the implications of the quantum phenomena and the measurement problem of orthodox quantum mechanics are far from conclusive. We appear to be left with many options: determinism (Bohm, Everett) or indeterminism (GRW), many worlds or a single one, particles or flashes or the wave function alone—all...

We have to talk about Schrödinger’s cat. Not just because Erwin Schrödinger found such a memorable way to illustrate his paradox. More importantly, his criticism hits the nail right on the head. Schrödinger formulates the so-called measurement problem of quantum mechanics, and this measurement problem shows why the naive understanding of quantum th...

Hugh Everett III is credited as the father of the Many Worlds theory, although the name was only later introduced by Brice DeWitt, and it is disputed historically whether Everett really believed in the reality of many worlds. What is not disputed is Everett’s insistence that we must take quantum mechanics seriously on all scales. He thus introduced...

All quantum theories have one thing in common: they agree that chance (or randomness) should feel at home in the theory. It is sometimes claimed that quantum randomness, or equivalently quantum probability, is irreducible, by which it is meant that there is just no way out of it. Quantum mechanical probability is expressed in Born’s statistical int...

We have omitted a lot in our reconstruction of the current state of relativistic quantum theory. For instance, the path integral formalism that is often hailed as a manifestly relativistic version of quantum field theory while, in fact, it is merely a technical reformulation that has just as many problems. Neither did we speak about string theory a...

Here we recall some mathematical basics of quantum mechanics about which there is no dispute. These fundamentals are equally relevant for all quantum mechanical theories (which are unfortunately—or rather, mistakenly—often referred to as interpretations). Our selection is also determined by our needs in later chapters.

When we look in textbooks on quantum theory to find the heart of the theory, one notion in particular stands out: the observable. In older representations, observables are self-adjoint operators on the Hilbert space of a system and they are supposed to describe the properties of a system which can be observed. In more modern texts (actually already...

Every course on quantum mechanics will at some point engage with the notion of “hidden variables”. The terminology is connected with the infamous no hidden variables theorems of von Neumann, Gleason, Kochen and Specker, and Bell, which assert that quantum mechanics does not allow for hidden variables.

The term “collapse theory” refers to an entire class of quantum theories that replace the Schrödinger equation by a non-linear time evolution for the wave function so that the superposition principle, which leads to the measurement problem, is no longer valid. For small systems, like single atoms, the violation of the superposition principle is bar...

We showed in the previous chapter that the Bohmian velocity of a particle cannot be measured according to ( 7.24). But by now there are many measurement experiments which report on successful measurements of Bohmian velocities. So what is going on? The answer is that these measurements are not of the form so far discussed. The new way of measuring...

This book discusses the physical and mathematical foundations of modern quantum mechanics and three realistic quantum theories that John Stuart Bell called "theories without observers" because they do not merely speak about measurements but develop an objective picture of the physical world. These are Bohmian mechanics, the GRW collapse theory, and...

The paper uses the concept of typicality to spell out an argument against Humean supervenience and the best system account of laws. It proves that, in a very general and robust sense, almost all possible Humean worlds have no Humean laws. They are worlds of irreducible complexity that do not allow for any systematization. After explaining typicalit...

The paper addresses the debate about the empirical status of particles versus wave functions in Bohmian quantum mechanics. It thereby clarifies questions and misconceptions about the role of the particles in the measurement process, the (un)reliability of position measurements ("surrealistic trajectories"), and the limited empirical access to parti...

This note clarifies some technical and conceptual details about the description of the measurement process in Bohmian mechanics and responds to a recent manuscript by Shan Gao (2019), wrongly claiming that Bohmian mechanics is inconsistent and doesn’t solve the measurement problem.

The paper addresses the debate about the empirical status of particles versus wave functions in Bohmian quantum mechanics. It thereby clarifies questions and misconceptions about the role of the particles in the measurement process, the (un)reliability of position measurements ("surrealistic trajectories"), and the limited empirical access to parti...

We discuss the no-go theorem of Frauchiger and Renner based on an “extended Wigner’s friend” thought experiment which is supposed to show that any single-world interpretation of quantum mechanics leads to inconsistent predictions if it is applicable on all scales. We show that no such inconsistency occurs if one considers a complete description of...

The paper discusses recent proposals by Carroll and Chen, as well as Barbour, Koslowski, and Mercati to explain the (thermodynamic) arrow of time without a Past Hypothesis, i.e. the assumption of a special (low-entropy) initial state of the universe. After discussing the role of the Past Hypothesis and the controversy about its status, we explain w...

In a recent article, Werndl and Frigg discuss the relationship between the Boltzmannian and Gibbsian framework of statistical mechanics, addressing in particular the question when equilibrium values calculated in both frameworks agree. In this paper, I address conceptual confusions that could arise from their discussion, concerning in particular th...

We discuss the "extended Wigner's friend" thought experiment proposed by D. Frauchiger and R.Renner [arXiv:1604.07422] that is supposed to show that "single-world interpretations" of quantum mechanics cannot be consistent if they are applicable on all scales. We explain why no such inconsistency occurs if one considers a complete description of the...

In a recent paper, Charlotte Werndl and Roman Frigg discuss the relationship between the Boltzmannian and Gibbsian framework of statistical mechanics, addressing in particular the question when equilibrium values calculated in both frameworks coincide. In this comment, I point out serious flaws in their work and try to put their results into proper...

The paper discusses and compares recent proposals by Carroll and Chen and Barbour et al. to explain the (thermodynamic) arrow of time without a Past Hypothesis, i.e. the assumption of a special (low-entropy) initial state. Defining a Boltzmann entropy for a classical gravitating universe, we argue that Newtonian gravity might actually provide examp...

The paper provides a critical discussion of the Super-Humean view of spacetime (Huggett's regularity account) and the “minimalist ontology” in terms of Leibnizian relations and primitive matter points, recently developed by Esfeld et al. It investigates, in particular, the empirical adequacy of the proposed metaphysics, arguing that Super-Humeanism...

The paper argues that far from challenging-or even refuting-Bohm's quantum theory, the no hidden-variables theorems in fact support the Bohmian ontology for quantum mechanics. The reason is that (i) all measurements come down to position measurements and (ii) Bohm's theory provides a clear and coherent explanation of the measurement outcome statist...

The paper argues that far from challenging – or even refuting – Bohm’s quantum theory, the no-hidden-variables theorems in fact support the Bohmian ontology for quantum mechanics. The reason is that (i) all measurements come down to position measurements and (ii) Bohm’s theory provides a clear and coherent explanation of the measurement outcome sta...

In a recent paper, Werndl and Frigg discuss the relationship between the Boltzmannian and Gibbsian framework of statistical mechanics, addressing in particular the question when equilibrium values calculated in both frameworks coincide. In this comment, I point out serious flaws in their work and try to put their results into proper context. I also...

We present a probabilistic proof of the mean field limit and propagation of chaos N-particle systems in three dimensions with positive (Coulomb) or negative (Newton) 1/r potentials scaling like 1/N and an N-dependent cut-off which scales like N-1/3+ϵ\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepa...

Using the example of classical electrodynamics, I argue that the concept of fields as mediators of particle interactions is fundamentally flawed and reflects a misguided attempt to retrieve Newtonian concepts in relativistic theories. This leads to various physical and metaphysical problems that are discussed in detail. In particular, I emphasize t...

The paper treats the validity problem of the non-relativistic Vlasov-Poisson equation in $d\geq 2$ dimensions. It is shown that the Vlasov-Poisson dynamics can be derived as a combined mean-field and point-particle limit of an N-particle Coulomb system of rigid charges. This requires a sufficiently fast convergence of the initial empirical distribu...

By means of the examples of classical and Bohmian quantum mechanics, we illustrate the well-known ideas of Boltzmann as to how one gets from laws defined for the universe as a whole to dynamical relations describing the evolution of subsystems. We explain how probabilities enter into this process, what quantum and classical probabilities have in co...

We present a microscopic derivation of the 3-dimensional relativistic Vlasov-Maxwell system as a combined mean field and point-particle limit of an $N$-particle system of rigid charges with $N$-dependent radius. The approximation holds for typical initial particle configurations, implying in particular propagation of chaos for the respective dynami...

While our physical description of the world does not contain an objective present, it still adheres to the notion of “instants” or “instantaneous states” that appear through the formulation of physical laws as initial value problems. That these ideas survived even the revolutionary transition from classical Newtonian space–time to relativistic spac...

The paper sets out a primitive ontology of the natural world in terms of primitive stuff, that is, stuff that has as such no physical properties at all, but that is not a bare substratum either, being individuated by metrical relations. We focus on quantum physics and employ identity-based Bohmian mechanics to illustrate this view, but point out th...

We present a simple model demonstrating that time-symmetric (advanced + retarded) relativistic interactions can account for statistical correlations violating the Bell inequalities while avoiding conspiracies as well as the commitment to instantaneous (direct space-like) influences. We provide an explicit statistical analysis of the model while hig...

We discuss Boltzmann's probabilistic explanation of the second law of thermodynamics providing a comprehensive presentation of what is called today the typicality account. Countering its misconception as an alternative explanation, we examine the relation between Boltzmann's H-theorem and the general typicality argument demonstrating the conceptual...

In my commentary, I will argue that the conclusions drawn in the paper Noncommutative Causality in Algebraic Quantum Field Theory by Gábor Hofer-Szabó are incorrect. As proven by J.S. Bell, a local common causal explanation of correlations violating the Bell inequality is impossible.

We present a simple model, demonstrating that time-symmetric relativistic interactions can account for correlations violating the Bell inequalities while avoiding conspiracies as well as the commitment to instantaneous influences. We emphasize the essential virtues and problems of such an account and discuss its relation to Bell's theorem.

In my commentary, I will argue that the conclusions drawn in the paper Noncommutative causality in algebraic quantum field theory by G\'abor Hofer-Szab\'o (and similar publications) are incorrect. As proven by J.S. Bell, a local common causal explanation of correlations violating the Bell inequality is impossible.

The article points out that the modern formulation of Bohm’s quantum theory, known as Bohmian mechanics, is committed only to particles’ positions and a law of motion. We explain how this view can avoid the open questions that the traditional view faces, according to which Bohm’s theory is committed to a wave-function that is a physical entity over...