arXiv subjects

Travis Norsen

Publications and source records attributed to Travis Norsen.

27 records · Page 2Linked to original sources

arXiv2006

Bell Locality and the Nonlocal Character of Nature

It is demonstrated that hidden variables of a certain type follow logically from a certain local causality requirement (``Bell Locality'') and the empirically well-supported predictions of quantum theory for the standard EPR-Bell setup. The demonstrated hidden variables are precisely those needed for the derivation of the Bell Inequalities. We thus refute the widespread view that empirical violations of Bell Inequalities leave open a choice of whether to reject (i) locality or (ii) hidden variables. Both principles are indeed assumed in the derivation of the inequalities, but since, as we demonstrate here, (ii) actually follows from (i), there is no choice but to blame the violation of Bell's Inequality on (i). Our main conclusion is thus that no Bell Local theory can be consistent with what is known from experiment about the correlations exhibited by separated particles. Aside from our conclusion being based on a different sense of locality this conclusion resembles one that has been advocated recently by H.P. Stapp. We therefore also carefully contrast the argument presented here to that proposed by Stapp.

quant-ph↗

arXiv2006

Counter-Factual Meaningfulness and the Bell and CHSH Inequalities

We discuss the role of counter-factual meaningfulness (a weaker cousin of "counter-factual definiteness") as a premise in the derivation of the Bell and CHSH inequalities. The basic question motivating the discussion is this: can the CHSH inequality, unlike the original Bell inequality, be derived without making a hidden-variables (or equivalent counter-factual definiteness) assumption? We answer, somewhat tentatively, in the negative, and suggest that an appropriately-modified version of the EPR argument is needed to rigorously establish that the empirical violation of Bell-type inequalities can only be blamed on the failure, in nature, of local causality.

quant-ph↗

arXiv2006

Intelligent Design in the Physics Classroom?

This fun polemical piece was written several months ago on a tip that the \emph{Chronicle of Higher Education} might be interested in publishing something like it. Sadly (both for me and, I think, for the \emph{Chronicle}'s readership) the editors didn't think it was of sufficient interest to the wider academic community. I am posting it here at the arxiv so that it can, nevertheless, be publicly available. If anyone out there wants to (suggest a place to) publish the piece, I'm all ears.

physics.pop-ph↗

arXiv2005

Einstein's Boxes

At the 1927 Solvay conference, Einstein presented a thought experiment intended to demonstrate the incompleteness of the quantum mechanical description of reality. In the following years, the thought experiment was picked up and modified by Einstein, de Broglie, and several other commentators into a simple scenario involving the splitting in half of the wave function of a single particle in a box. In this paper we collect together several formulations of this thought experiment from the existing literature; analyze and assess it from the point of view of the Einstein-Bohr debates, the EPR dilemma, and Bell's theorem; and generally lobby for Einstein's Boxes taking its rightful place alongside similar but historically better-known quantum mechanical thought experiments such as EPR and Schroedinger's Cat.

quant-ph↗

arXiv2005

EPR and Bell Locality

A new formulation of the EPR argument is presented, one which uses John Bell's mathematically precise local causality condition in place of the looser locality assumption which was used in the original EPR paper and on which Niels Bohr seems to have based his objection to the EPR argument. The new formulation of EPR bears a striking resemblance to Bell's derivation of his famous inequalities. The relation between these two arguments -- in particular, the role of EPR as part one of Bell's two-part argument for nonlocality -- is also discussed in detail.

quant-ph↗

arXiv2004

Quantum Theory: Interpretation Cannot be Avoided

This essay is a response to the (March 2000) Physics Today Opinion article "Quantum Theory Needs No Interpretation" by Fuchs and Peres. It was written several years ago and has been collecting electronic dust ever since Physics Today said they weren't interested. We post it here with the hope that it may still be of some interest.

quant-ph↗

arXiv2002

Mixed Kaon Condensation in CFL Matter

Previous work on high-density QCD suggests that the ground state configuration in the presence of a non-zero neutrino chemical potential consists of CFL matter plus a homogenous condensate of neutral and positive kaons. We consider here the stability of this homogenous configuration toward the production of a charge-separated mixed phase, and find that the system is indeed stable against the production of such a heterogenous configuration. We identify the critical value of the fine structure constant which would allow for phase separation. We also derive dispersion relations for the low-lying excitations above the kaon-condensed ground state and discuss their possible phenomenological implications.

hep-ph↗

arXiv2002

Strangeness Nucleation in Neutron Star Matter

We study the transition from npe-type nuclear matter (consisting of neutrons, protons, and electrons) to matter containing strangeness, using a Walecka-type model predicting a first-order kaon-condensate phase transition. We examine the free energy of droplets of K-matter as the density, temperature, and neutrino fraction are varied. Langer nucleation rate theory is then used to approximate the rate at which critical droplets of the new phase are produced by thermal fluctuations, thus giving an estimate of the time required for the new (mixed) phase to appear at various densities and various times in the cooling history of the proto-neutron star. We also discuss the famous difficulty of "simultaneous weak interactions" which we connect to the literature on non-topological solitons. Finally, we discuss the implications of our results to several phenomenological issues involving neutron star phase transitions.

astro-ph↗

arXiv2000

First Order Kaon Condensation in Neutron Stars: Finite Size Effects in the Mixed Phase

We study the role of Coulomb and surface effects on the phase transition from dense nuclear matter to a mixed phase of nuclear and kaon-condensed matter. We calculate corrections to the bulk calculation of the equation of state (EOS) and the critical density for the transition by solving explicitly for spherical, cylindrical, and planar structures. The importance of Debye screening in the determination of the charged particle profiles is studied in some detail. We find that the surface and Coulomb contributions to the energy density are small, but that they play an important role in the determination of the critical pressure for the transition, as well as affecting the size and geometry of favored structures. This changes the EOS over a wide range of pressure and consequently increases the maximum mass by about 0.1 solar masses. Implications for transport properties of the mixed phase are also discussed.

nucl-th↗