In this paper, I critically assess different interpretations of Bohmianmechanics that are not committed to an ontology based on the wave function being an actual physical object that inhabits configuration space. More specifically, my aim is to explore the connection between the denial of configuration space realism and another interpretive debate that is specific to Bohmianmechanics: the quantum potential versus guidance approaches. Whereas defenders of the quantum potential approach to the theory claim that (...) class='Hi'>Bohmianmechanics is better formulated as quasi-Newtonian, via the postulation of forces proportional to acceleration; advocates of the guidance approach defend the notion that the theory is essentially first-order and incorporates some concepts akin to those of Aristotelian physics. Here I analyze whether the desideratum of an interpretation of Bohmianmechanics that is both explanatorily adequate and not committed to configuration space realism favors one of these two approaches to the theory over the other. Contrary to some recent claims in the literature, I argue that the quasi-Newtonian approach based on the idea of a quantum potential does not come out the winner. (shrink)
Bohmianmechanics, which is also called the de Broglie-Bohm theory, the pilot-wave model, and the causal interpretation of quantum mechanics, is a version of quantum theory discovered by Louis de Broglie in 1927 and rediscovered by David Bohm in 1952. It is the simplest example of what is often called a hidden variables interpretation of quantum mechanics. In Bohmianmechanics a system of particles is described in part by its wave function, evolving, as usual, (...) according to Schrödinger's equation. However, the wave function provides only a partial description of the system. This description is completed by the specification of the actual positions of the particles. The latter evolve according to the.. (shrink)
Bohmianmechanics is a theory about point particles moving along trajectories. It has the property that in a world governed by Bohmianmechanics, observers see the same statistics for experimental results as predicted by quantum mechanics. Bohmianmechanics thus provides an explanation of quantum mechanics. Moreover, the Bohmian trajectories are defined in a non-conspiratorial way by a few simple laws.
The paper presents an inquiry into the question regarding the compatibility of Bohmianmechanics, intended as a non-local theory of moving point-like particles, with background independence. This issue is worth being investigated because, if the Bohmian framework has to be of some help in developing new physics, it has to be compatible with the most well-established traits of modern physics, background independence being one of such traits. The paper highlights the fact that the notion of background independence (...) in the context of spacetime physics is slippery and interpretation-laden. It is then suggested that the best-matching framework developed by Julian Barbour might provide a robust enough meaning of background independence. The structure of Bohmian dynamics is evaluated against this framework, reaching some intermediate results that speak in favor of the fact that Bohmianmechanics can be made background independent. (shrink)
The paper points out that the modern formulation of Bohm’s quantum theory known as Bohmianmechanics 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 and above the particles, although it is defined on configuration space instead of three-dimensional space. We then enquire into the status (...) of the law of motion, elaborating on how the main philosophical options to ground a law of motion, namely Humeanism and dispositionalism, can be applied to Bohmianmechanics. In conclusion, we sketch out how these options apply to primitive ontology approaches to quantum mechanics in general. (shrink)
David Lewis is a natural target for those who believe that findings in quantum physics threaten the tenability of traditional metaphysical reductionism. Such philosophers point to allegedly holistic entities they take both to be the subjects of some claims of quantum mechanics and to be incompatible with Lewisian metaphysics. According to one popular argument, the non-separability argument from quantum entanglement, any realist interpretation of quantum theory is straightforwardly inconsistent with the reductive conviction that the complete physical state of the (...) world supervenes on the intrinsic properties of and spatio-temporal relations between its point-sized constituents. Here I defend Lewis's metaphysical doctrine, and traditional reductionism more generally, against this alleged threat from quantum holism. After presenting the non-separability argument from entanglement, I show that Bohmianmechanics, an interpretation of quantum mechanics explicitly recognized as a realist one by proponents of the non-separability argument, plausibly rejects a key premise of that argument. Another holistic worry for Humeanism persists, however, the trouble being the apparently holistic character of the Bohmian pilot wave. I present a Humean strategy for addressing the holistic threat from the pilot wave by drawing on resources from the Humean best system account of laws. (shrink)
Bohmianmechanics and the Ghirardi-Rimini-Weber theory provide opposite resolutions of the quantum measurement problem: the former postulates additional variables (the particle positions) besides the wave function, whereas the latter implements spontaneous collapses of the wave function by a nonlinear and stochastic modification of Schrödinger's equation. Still, both theories, when understood appropriately, share the following structure: They are ultimately not about wave functions but about 'matter' moving in space, represented by either particle trajectories, fields on space-time, or a discrete (...) set of space-time points. The role of the wave function then is to govern the motion of the matter. (shrink)
We consider the problem of whether there are deterministic theories describing the evolution of an individual physical system in terms of the definite trajectories of its constituent particles and which stay in the same relation to quantum mechanics as Bohmianmechanics but which differ from the latter for what concerns the trajectories followed by the particles. Obviously, one has to impose on the hypothetical alternative theory precise physical requirements. We analyze various such constraints and we show step (...) by step how to meet them. This way of attacking the problem turns out to be useful also from a pedagogical point of view since it allows one to recall and focus on some relevant features of Bohm's theory. One of the central requirements we impose on the models we are going to analyze has to do with their transformation properties under the transformation of the extended Galilei group. In a context like the one we are interested in, one can put forward various requests that we refer to as physical and genuine covariance and invariance. Other fundamental requests are that the theory allows the description of isolated physical systems as well as that it leads to a solution (in the same sense as Bohmianmechanics) of the measurement problem. We show that, even when all the above conditions are taken into account, there are infinitely many inequivalent (from the point of view of the trajectories) bohmian-like theories reproducing the predictions of quantum mechanics. This raises some interesting questions about the meaning of Bohmianmechanics. (shrink)
Many recent results suggest that quantum theory is about information, and that quantum theory is best understood as arising from principles concerning information and information processing. At the same time, by far the simplest version of quantum mechanics, Bohmianmechanics, is concerned, not with information but with the behavior of an objective microscopic reality given by particles and their positions. What I would like to do here is to examine whether, and to what extent, the importance of (...) information, observation, and the like in quantum theory can be understood from a Bohmian perspective. I would like to explore the hypothesis that the idea that information plays a special role in physics naturally emerges in a Bohmian universe. (shrink)
Bohmianmechanics is a theory about point particles moving along trajectories. It has the property that in a world governed by Bohmianmechanics, observers see the same statistics for experimental results as predicted by quantum mechanics. Bohmianmechanics thus provides an explanation of quantum mechanics. Moreover, the Bohmian trajectories are defined in a non-conspiratorial way by a few simple laws.
Bohmianmechanics is a quantum theory with a clear ontology. To make clear what we mean by this, we shall proceed by recalling first what are the problems of quantum mechanics. We shall then briefly sketch the basics of Bohmianmechanics and indicate how Bohmianmechanics solves these problems and clarifies the status and the role of of the quantum formalism.
When I was young I was fascinated by the quantum revolution: the transition from classical definiteness and determinism to quantum indeterminacy and uncertainty, from classical laws that are indifferent, if not hostile, to the human presence, to quantum laws that fundamentally depend upon an observer for their very meaning. I was intrigued by the radical subjectivity, as expressed by Heisenberg’s assertion [3] that “The idea of an objective real world whose smallest parts exist objectively in the same sense as stones (...) or trees exist, independently of whether or not we observe them . . . is impossible . . . ” It is true that I did not really understand what the quantum side of this transition in fact entailed, but that very fact made quantum mechanics seem to me all the more exciting. I was eager to learn precisely what the alluring quantum mysteries might mean, what kind of world they describe, as well as exactly what evidence could compel—or at least support—such radical conclusions. (shrink)
Square billiards are quantum systems complying with the dynamical quantum-classical correspondence. Hence an initially localized wavefunction launched along a classical periodic orbit evolves along that orbit, the spreading of the quantum amplitude being controlled by the spread of the corresponding classical statistical distribution. We investigate wavepacket dynamics and compute the corresponding de Broglie-Bohm trajectories in the quantum square billiard. We also determine the trajectories and statistical distribution dynamics for the equivalent classical billiard. Individual Bohmian trajectories follow the streamlines of (...) the probability flow and are generically non-classical. This can also hold even for short times, when the wavepacket is still localized along a classical trajectory. This generic feature of Bohmian trajectories is expected to hold in the classical limit. We further argue that in this context decoherence cannot constitute a viable solution in order to recover classicality. (shrink)
We derive for Bohmianmechanics topological factors for quantum systems with a multiply-connected configuration space Q. These include nonabelian factors corresponding to what we call holonomy-twisted representations of the fundamental group of Q. We employ wave functions on the universal covering space of Q. As a byproduct of our analysis, we obtain an explanation, within the framework of Bohmianmechanics, of the fact that the wave function of a system of identical particles is either symmetric or (...) anti-symmetric. (shrink)
Even though the Bohmian trajectories given by integral curves of the conserved Klein-Gordon current may involve motions backwards in time, the natural relativistic probability density of particle positions is well-defined. The Bohmian theory predicts subtle deviations from the statistical predictions of more conventional formulations of quantum theory, but it seems that no present experiment rules this theory out. The generalization to the case of many particles or strings is straightforward, provided that a preferred foliation of spacetime is given.
It is usual to identify initial conditions of classical dynamical systems with mathematical real numbers. However, almost all real numbers contain an infinite amount of information. I argue that a finite volume of space can’t contain more than a finite amount of information, hence that the mathematical real numbers are not physically relevant. Moreover, a better terminology for the so-called real numbers is “random numbers”, as their series of bits are truly random. I propose an alternative classical mechanics, which (...) is empirically equivalent to classical mechanics, but uses only finite-information numbers. This alternative classical mechanics is non-deterministic, despite the use of deterministic equations, in a way similar to quantum theory. Interestingly, both alternative classical mechanics and quantum theories can be supplemented by additional variables in such a way that the supplemented theory is deterministic. Most physicists straightforwardly supplement classical theory with real numbers to which they attribute physical existence, while most physicists reject Bohmianmechanics as supplemented quantum theory, arguing that Bohmian positions have no physical reality. (shrink)
It is well known that density matrices can be used in quantum mechanics to represent the information available to an observer about either a system with a random wave function or a system that is entangled with another system. We point out another role, previously unnoticed in the literature, that a density matrix can play: it can be the “conditional density matrix,” conditional on the configuration of the environment. A precise definition can be given in the context of (...) class='Hi'>Bohmianmechanics, whereas orthodox quantum mechanics is too vague to allow a sharp definition, except perhaps in special cases. In contrast to statistical and reduced density matrices, forming the conditional density matrix involves no averaging. In Bohmianmechanics with spin, the conditional density matrix replaces the notion of conditional wave function, as the object with the same dynamical significance as the wave function of a Bohmian system. (shrink)
The property of fundamental mechanical theories which allows to treat compound objects as particles under suitable conditions is considered. It is argued that such a property, called compoundation invariance, is a nonreleasable property of any mechanical theory not declaring to which elementary constituents it applies. Compoundation invariance is discussed in the framework of Bohmianmechanics. It is found that standard Bohmianmechanics satisfies the requirement of compoundation invariance, with some reservation in the case of compound objects (...) with spin. On the contrary that requirement is violated when additional terms are added to the standard velocity. (shrink)
Bohmianmechanics faces an underdetermination problem: when it comes to solving the measurement problem, alternatives to the Bohmian guidance equation work just as well as the official guidance equation. One way to argue that the guidance equation is superior to its rivals is to use a symmetry argument: of the candidate guidance equations, the official guidance equation is the simplest Galilean-invariant candidate. This symmetry argument---if it worked---would solve the underdetermination problem. But the argument does not work. It (...) fails because it rests on assumptions about how Galilean transformations (especially boosts) act on the wavefunction that are (in this context) unwarranted. My discussion has larger morals about the physical significance of certain mathematical results (like, for example, Wigner's theorem) in non-orthodox interpretations of quantum mechanics. (shrink)
The relationship between mathematical formalism, physical interpretation and epistemological appraisal in the practice of physical theorizing is considered in the context of Bohmianmechanics. After laying outthe formal mathematical postulates of thetheory and recovering the historical roots ofthe present debate over the meaning of Bohmianmechanics from the early debate over themeaning of Schrödinger's wave mechanics,several contemporary interpretations of Bohmianmechanics in the literature are discussed andcritiqued with respect to the aim of causalexplanation and an alternative interpretationis proposed. Throughout, (...) the over-arching aimis to exhibit the connections betweenmathematical, ontological and methodologicalquestions in physical theory and to reflect onthe rationality of physical theorizing in lightof the present case. (shrink)
It is difficult to articulate how we should take a realist attitude towards Bohmianmechanics because there are many versions of it. This paper aims to clarify the realist commitments of Bohmianmechanics and how we can understand it from a general scientific realist perspective. I use the box experiment, a double-slit like experiment conducted by Cardone et al. :1–13, 2004; Int J Mod Phys B 20:1107–1121, 2006), as a working example to argue that a causal (...) realist account that is applicable to Bohmianmechanics, has to be supplemented with the use of Inference to the Best Explanation. The reason is because causal realism on its own does not form a sufficient basis for realism about Bohmianmechanics. In particular, I argue that the existence of the pilot wave explains why we observe an anomalous interference effect in the experiment of Cardone et al. The conclusion to draw is that a complete realist account about Bohmianmechanics rests on explanatory considerations. (shrink)
In Bohmianmechanics the distribution |ψ|2 is regarded as the equilibrium distribution. We consider its uniqueness, finding that it is the unique equivariant distribution that is also a local functional of the wave function ψ.
Bohmianmechanics is a quantum theory without observers. This means that neither the act of observation nor the notion of observer play any role in defining the theory, the theory is not about observers and observation, and it explains all non relativistic quantum phenomena. The theory is about something primitive', the basic ontology, and the laws for that are given. Bohmianmechanics is a deterministic theory of point particles. Like Newtonian mechanics it is invariant under (...) Galilei transformations, but unlike Newtonian mechanics it is a first-order theory, acceleration is not a concept entering the law of motion. Rather this law directly determines the velocities of the particles as follows. (shrink)
A persistent question about the deBroglie–Bohm interpretation of quantum mechanics concerns the understanding of Born’s rule in the theory. Where do the quantum mechanical probabilities come from? How are they to be interpreted? These are the problems of emergence and interpretation. In more than 50 years no consensus regarding the answers has been achieved. Indeed, mirroring the foundational disputes in statistical mechanics, the answers to each question are surprisingly diverse. This paper is an opinionated survey of this literature. (...) While acknowledging the pros and cons of various positions, it defends particular answers to how the probabilities emerge from Bohmianmechanics and how they ought to be interpreted. (shrink)
The popular impression of Bohmianmechanics is that it is standard quantum mechanics with the addition of some extra gadgets---exact particle positions and a guiding equation for particle trajectories---the advantages being that the gadgets pave the way for a resolution of the measurement problem that eschews state vector reduction while restoring the determinism lost in standard quantum mechanics. In fact, the Bohmianmechanics departs in significant ways from standard quantum mechanics. By itself this (...) is not a basis for criticism; indeed, it makes Bohmianmechanics all the more interesting. But Bohmianmechanics is not, as the popular impression would have it, empirically equivalent to standard quantum mechanics in terms of probabilistic predictions for the outcomes of measurements of quantum observables. Indeed, in physically important applications to systems for which standard quantum mechanics delivers empirically well-confirmed probabilistic predictions, the sophisticated form of Bohmianmechanics designed to prove the global existence of Bohmian particle trajectories fails to deliver unequivocal predictions---of even a probabilistic variety---for the future behavior of said systems. Possible responses to this lacuna are discussed. (shrink)
Although during the last decades the philosophy of chemistry has greatly extended its thematic scope, the main difficulties appear in the attempt to link the chemical description of atoms and molecules and the description supplied by quantum mechanics. The aim of this paper is to analyze how the difficulties that threaten the continuous conceptual link between molecular chemistry and quantum mechanics can be overcome or, at least, moderated from the perspective of BM. With this purpose, in “The quantum-mechanical (...) challenges” section the foundational incompatibility between chemical and SQM descriptions will be briefly recalled. “Bohmianmechanics” section will be devoted to explain the main features of BM. In “Empirical equivalence and underdetermination” section, the consequences of the empirical equivalence between SQM and BM will be discussed. Finally, in the Conclusion, we will stress the scope of the obtained conclusions and the philosophical difficulties that still remain even after adopting BM for foundational purposes. (shrink)
A persistent question about the deBroglie–Bohm interpretation of quantum mechanics concerns the understanding of Born’s rule in the theory. Where do the quantum mechanical probabilities come from? How are they to be interpreted? These are the problems of emergence and interpretation. In more than 50 years no consensus regarding the answers has been achieved. Indeed, mirroring the foundational disputes in statistical mechanics, the answers to each question are surprisingly diverse. This paper is an opinionated survey of this literature. (...) While acknowledging the pros and cons of various positions, it defends particular answers to how the probabilities emerge from Bohmianmechanics and how they ought to be interpreted. (shrink)
Although during the last decades the philosophy of chemistry has greatly extended its thematic scope, the main difficulties appear in the attempt to link the chemical description of atoms and molecules and the description supplied by quantum mechanics. The aim of this paper is to analyze how the difficulties that threaten the continuous conceptual link between molecular chemistry and quantum mechanics can be overcome or, at least, moderated from the perspective of BM. With this purpose, in “The quantum-mechanical (...) challenges” section the foundational incompatibility between chemical and SQM descriptions will be briefly recalled. “Bohmianmechanics” section will be devoted to explain the main features of BM. In “Empirical equivalence and underdetermination” section, the consequences of the empirical equivalence between SQM and BM will be discussed. Finally, in the Conclusion, we will stress the scope of the obtained conclusions and the philosophical difficulties that still remain even after adopting BM for foundational purposes. (shrink)
In a recent article [1], Wiseman has proposed the use of so-called weak measurements for the determination of the velocity of a quantum particle at a given position, and has shown that according to quantum mechanics the result of such a procedure is the Bohmian velocity of the particle. Although Bohmianmechanics is empirically equivalent to variants based on velocity formulas different from the Bohmian one, and although it has been proven that the velocity in (...)Bohmianmechanics is not measurable, we argue here for the somewhat paradoxical conclusion that Wiseman’s weak measurement procedure indeed constitutes a genuine measurement of velocity in Bohmianmechanics. We reconcile the apparent contradictions and elaborate on some of the different senses of measurement at play here. (shrink)
Bohm developed the Bohmianmechanics, in which the Schrödinger equation is transformed into two differential equations: a continuity equation and an equation of motion similar to the Newtonian equation of motion. This transformation can be executed both for single-particle systems and for many-particle systems. Later, Kuzmenkov and Maksimov used basic quantum mechanics for the derivation of many-particle quantum hydrodynamics including one differential equation for the mass balance and two differential equations for the momentum balance, and we extended (...) their analysis in a prework for the case that the particle ensemble consists of different particle sorts. The purpose of this paper is to show how the differential equations of MPQHD can be derived for such a particle ensemble with the differential equations of BM as a starting point. Moreover, our discussion clarifies that the differential equations of MPQHD are more suitable for an analysis of many-particle systems than the differential equations of BM because the differential equations of MPQHD depend on a single position vector only while the differential equations of BM depend on the complete set of all particle coordinates. (shrink)
Bosonic and fermionic particle currents can be introduced in a more unified way, with the cost of introducing a preferred spacetime foliation. Such a unified treatment of bosons and fermions naturally emerges from an analogous superstring current, showing that the preferred spacetime foliation appears only at the level of effective field theory, not at the fundamental superstring level. The existence of the preferred spacetime foliation allows an objective definition of particles associated with quantum field theory in curved spacetime. Such an (...) objective definition of particles makes the Bohmian interpretation of particle quantum mechanics more appealing. The superstring current allows a consistent Bohmian interpretation of superstrings themselves, including a Bohmian description of string creation and destruction in terms of string splitting. The Bohmian equations of motion and the corresponding probabilistic predictions are fully relativistic covariant and do not depend on the preferred foliation. (shrink)
We clarify the significance of quasiprobability in quantum mechanics that is relevant in describing physical quantities associated with a transition process. Our basic quantity is Aharonov’s weak value, from which the QP can be defined up to a certain ambiguity parameterized by a complex number. Unlike the conventional probability, the QP allows us to treat two noncommuting observables consistently, and this is utilized to embed the QP in Bohmianmechanics such that its equivalence to quantum mechanics (...) becomes more transparent. We also show that, with the help of the QP, Bohmianmechanics can be recognized as an ontological model with a certain type of contextuality. (shrink)
This paper explains the phenomenon of `entanglement exchange' within the Bohmian approach to quantum mechanics. After explaining Bohmianmechanics and entanglement exchange, in which pairs of particles become entangled without ever interacting causally in the usual, unitary sense, our aim is to use this example, to illustrate how the `pilot wave' mediates non-local correlations. The discussion thus gives a useful new way to think about entanglement exchange, and clarifies the structure of Bohmianmechanics.
Bohmian trajectories have been used for various purposes, including the numerical simulation of the time-dependent Schr¨ odinger equation and the visualization of time-dependent wave functions. We review the purpose they were invented for: to serve as the foundation of quantum mechanics, i.e., to explain quantum mechanics in terms of a theory that is free of paradoxes and allows an understanding that is as clear as that of classical mechanics. Indeed, they succeed in serving that purpose in (...) the context of a theory known as Bohmianmechanics, to which this article is an introduction. (shrink)
This paper continues an earlier work by considering in what sense and to what extent identical Bohmian-mechanical particles in many-particle systems can be considered indistinguishable. We conclude that while whether identical Bohmian-mechanical particles ace considered to be “statistically (in)distinguishable” is a matter of theory choice underdetermined by logic and experiment, such particles are in any case “physically distinguishable.”.
The theory of weak measurements developed by Aharonov and coworkers has been applied by them and others to several interesting problems in which the system of interest is both pre- and post-selected. When the probability of successful post-selection is very small the prediction for the weak value of the measured quantity is often “bizarre” and sometimes controversial, lying outside the range of possibility for a classical system or for a quantum system in the absence of post-selection (e.g. negative kinetic energies (...) associated with particles found immediately after the weak measurement deep inside a classically forbidden region). In Bohmianmechanics a quantum particle is postulated to be a point-like particle which is always accompanied by a wave which probes its environment and guides its motion accordingly. Hence, from the point of view of this theory, it is natural to ask whether the measured weak value under consideration is a property of the point-like particle or of the wave (or of both) and what, if anything, it is that is actually being measured. In this paper, weak measurements of position, momentum and kinetic energy are considered for very simple case studies with these questions in mind. (shrink)
This paper argues for a broadly dispositionalist approach to the ontology of Bohmianmechanics . It first distinguishes the ‘minimal’ and the ‘causal’ versions of Bohm’s theory, and then briefly reviews some of the claims advanced on behalf of the ‘causal’ version by its proponents. A number of ontological or interpretive accounts of the wave function in BM are then addressed in detail, including configuration space, multi-field, nomological, and dispositional approaches. The main objection to each account is reviewed, (...) namely the ‘problem of perception’, the ‘problem of communication’, the ‘problem of temporal laws’, and the ‘problem of under-determination’. It is then shown that a version of dispositionalism overcomes the under-determination problem while providing neat solutions to the other three problems. A pragmatic argument is thus furnished for the use of dispositions in the interpretation of the theory more generally. The paper ends in a more speculative note by suggesting ways in which a dispositionalist interpretation of the wave function is in addition able to shed light upon some of the claims of the proponents of the causal version of BM. (shrink)
Although during the last decades the philosophy of chemistry has greatly extended its thematic scope, the main difficulties appear in the attempt to link the chemical description of atoms and molecules and the description supplied by quantum mechanics. The aim of this paper is to analyze how the difficulties that threaten the continuous conceptual link between molecular chemistry and quantum mechanics can be overcome or, at least, moderated from the perspective of BM. With this purpose, in “The quantum-mechanical (...) challenges” section the foundational incompatibility between chemical and SQM descriptions will be briefly recalled. “Bohmianmechanics” section will be devoted to explain the main features of BM. In “Empirical equivalence and underdetermination” section, the consequences of the empirical equivalence between SQM and BM will be discussed. Finally, in the Conclusion, we will stress the scope of the obtained conclusions and the philosophical difficulties that still remain even after adopting BM for foundational purposes. (shrink)
It is argued that in Bohmianmechanics the effective wave function of a subsystem of the universe does not encode the influences of other particles on the subsystem. This suggests that the ontology of Bohmianmechanics does not consist only in Bohmian particles and their positions. It is nonetheless pointed out that since the wave function in configuration space may represent the state of ergodic motion of non-Bohmian particles in three-dimensional space, the ontology of (...)Bohmianmechanics may still consist only in particles. (shrink)
This note clarifies several details about the description of the measurement process in Bohmianmechanics and responds to a recent preprint by Shan Gao, wrongly claiming a contradiction in the theory.
The article 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...
Several situations, in which an empty wave causes an observable effect, are reviewed. They include an experiment showing ‘‘surrealistic trajectories’’ proposed by Englert et al. and protective measurement of the density of the quantum state. Conditions for observable effects due to empty waves are derived. The possibility (in spite of the existence of these examples) of minimalistic interpretation of Bohmian quantum mechanics in which only Bohmian positions supervene on our experience is discussed.
