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Full-Text Articles in Physics
Can The Wave Function In Configuration Space Be Replaced By Single-Particle Wave Functions In Physical Space?, Travis Norsen, Damiano Marian, Xavier Oriols
Can The Wave Function In Configuration Space Be Replaced By Single-Particle Wave Functions In Physical Space?, Travis Norsen, Damiano Marian, Xavier Oriols
Physics: Faculty Publications
The ontology of Bohmian mechanics includes both the universal wave function (living in 3N-dimensional configuration space) and particles (living in ordinary 3-dimensional physical space). Proposals for understanding the physical significance of the wave function in this theory have included the idea of regarding it as a physically-real field in its 3N-dimensional space, as well as the idea of regarding it as a law of nature. Here we introduce and explore a third possibility in which the configuration space wave function is simply eliminated – replaced by a set of single-particle pilot-wave fields living in ordinary physical space. Such a re-formulation …
Are There Really Two Different Bell’S Theorems?, Travis Norsen
Are There Really Two Different Bell’S Theorems?, Travis Norsen
Physics: Faculty Publications
This is a polemical response to Howard Wiseman’s recent paper, “The two Bell’s theorems of John Bell”. Wiseman argues that, in 1964, Bell established a conflict between the quantum mechanical predictions and the joint assumptions of determinism and (what is now usually known as) “parameter independence”. Only later, in 1976, did Bell, according to Wiseman, first establish a conflict between the quantum mechanical predictions and locality alone (in the specific form that Bell would sometimes call “local causality”). Thus, according to Wiseman, the long-standing disagreements about what, exactly, Bell’s theorem does and does not prove can be understood largely as …
Weak Measurement And Bohmian Conditional Wave Functions, Travis Norsen
Weak Measurement And Bohmian Conditional Wave Functions, Travis Norsen
Physics: Faculty Publications
It was recently pointed out (and demonstrated experimentally) by Lundeen et al. that the wave function of a particle (more precisely, the wave function possessed by each member of an ensemble of identically-prepared particles) can be "directly measured" using weak measurement. Here it is shown that if this same technique is applied, with appropriate post-selection, to one particle from a (perhaps entangled) multi-particle system, the result is precisely the so-called "conditional wave function" of Bohmian mechanics. Thus, a plausibly operationalist method for defining the wave function of a quantum mechanical sub-system corresponds to the natural definition of a sub-system wave …
The Pilot-Wave Perspective On Spin, Travis Norsen
The Pilot-Wave Perspective On Spin, Travis Norsen
Physics: Faculty Publications
The alternative pilot-wave theory of quantum phenomena—associated especially with Louis de Broglie, David Bohm, and John Bell—reproduces the statistical predictions of ordinary quantum mechanics but without recourse to special ad hoc axioms pertaining to measurement. That (and how) it does so is relatively straightforward to understand in the case of position measurements and, more generally, measurements, whose outcome is ultimately registered by the position of a pointer. Despite a widespread belief to the contrary among physicists, the theory can also account successfully for phenomena involving spin. The main goal of this paper is to explain how the pilot- wave theory’s …
Can Bohmian Mechanics Be Made Relativistic?, Detlef Dürr, Sheldon Goldstein, Travis Norsen, Ward Struyve, Nino Zaghì
Can Bohmian Mechanics Be Made Relativistic?, Detlef Dürr, Sheldon Goldstein, Travis Norsen, Ward Struyve, Nino Zaghì
Physics: Faculty Publications
In relativistic space-time, Bohmian theories can be formulated by introducing a privileged foliation of space-time. The introduction of such a foliation – as extra absolute space-time structure – would seem to imply a clear violation of Lorentz invariance, and thus a conflict with fundamental relativity. Here, we consider the possibility that, instead of positing it as extra structure, the required foliation could be covariantly determined by the wave function. We argue that this allows for the formulation of Bohmian theories that seem to qualify as fundamentally Lorentz invariant. We conclude with some discussion of whether or not they might also …
Yet Another Snapshot Of Foundational Attitudes Toward Quantum Mechanics, Travis Norsen, Sarah Nelson
Yet Another Snapshot Of Foundational Attitudes Toward Quantum Mechanics, Travis Norsen, Sarah Nelson
Physics: Faculty Publications
A survey probing respondents' views on various foundational issues in quantum mechanics was recently created by Schlosshauer, Kofler, and Zeilinger [arXiv:1301.1069] and then given to 33 participants at a quantum foundations conference. Here we report the results of giving this same survey to the attendees at another recent quantum foundations conference. While it is rather difficult to conclude anything of scientific significance from the poll, the results do strongly suggest several interesting cultural facts -- for example, that there exist, within the broad field of "quantum foundations", sub-communities with quite different views, and that (relatedly) there is probably …
The Pilot-Wave Perspective On Quantum Scattering And Tunneling, Travis Norsen
The Pilot-Wave Perspective On Quantum Scattering And Tunneling, Travis Norsen
Physics: Faculty Publications
The de Broglie-Bohm “pilot-wave” theory replaces the paradoxical wave-particle duality of ordinary quantum theory with a more mundane and literal kind of duality: each individual photon or electron comprises a quantum wave (evolving in accordance with the usual quantum mechanical wave equation) and a particle that, under the influence of the wave, traces out a definite trajectory. The definite particle trajectory allows the theory to account for the results of experiments without the usual recourse to additional dynamical axioms about measurements. Instead, one need simply assume that particle detectors click when particles arrive at them. This alternative understanding of quantum …
Latticeeasy: A Program For Lattice Simulations Of Scalar Fields In An Expanding Universe, Gary Felder, Igor Tkachev
Latticeeasy: A Program For Lattice Simulations Of Scalar Fields In An Expanding Universe, Gary Felder, Igor Tkachev
Physics: Faculty Publications
We describe a C++ program that we have written and made available for calculating the evolution of interacting scalar fields in an expanding universe. The program is particularly useful for the study of reheating and thermalization after inflation. The program and its full documentation are available on the Web at http://physics.stanford.edu/gfelder/latticeeasy. In this paper we provide a brief overview of what the program does and what it is useful for.