When Greenberger, Horne and Zeilinger meet Wigner's Friend

A general argument is presented against relativistic, unitary, single-outcome quantum mechanics. This is achieved by combining the Wigner's Friend thought experiment with measurements on a Greenberger-Horne-Zeilinger (GHZ) state, and describing the evolution of the quantum state in various inertial frames. Assuming unitary quantum mechanics and single outcomes, the result is that the Born rule must be violated in some inertial frame: in that frame, outcomes are obtained for which no corresponding term exists in the pre-measurement wavefunction.Comment: 16 pages, 1 figur

Increasing Student Success at Minority-Serving Institutions: Findings From the BEAMS Project

Details the five-step process used at over one hundred campuses to craft data-driven action plans to improve student success as part of the BEAMS (Building Engagement and Attainment for Minority Students) initiative. Includes case studies

Optimisation of connections to a fibre network

Stronger competition together with the development of new technologies have forced the Telecom Service Providers (TSP's) in the Netherlands to look for sophisticated optimisation methods to reduce the costs of their communication services especially for new areas such as the application of fibre technology.Fibre is being considered as the transmission medium of the future because fibre deadens the signals much less than the traditional media such as copper and coax, a lot of data can be transmitted at the same time and there are only a few failures. Another advantage is that fibre cables are thin and light so that they can be put into the ground rather easily.This article describes optimisation models with the objective to minimise the costs of constructing and managing a fibre network.The optimisation models have been developed to support decisions about the design and use of a fibre network and are based on the practical situation at Enertel being one of the new TSP’s. For Enertel a national backbone was already realised. The main problem to be solved concerned the optimisation of the access to the fibre network.

Repton model of gel electrophoresis in the long chain limit

Reptation governs motion of long polymers through a confining environment. Slack enters at the ends and diffuses along the polymer as stored length. The rate at which stored length diffuses limits the speed at which the chain can drift. This paper relates the rate of stored length diffusion to the conformation of the tube within which the polymer is confined. In the scaling limit of long polymer chains and weak applied electric fields, holding the product of polymer length times field finite, the tube length and stored length density take on their zero-field values. The drift velocity then depends only on the the polymer's end-to-end separation in the direction of the field.Comment: 14 pages,4 figure

When Greenberger, Horne and Zeilinger meet Wigner's Friend

A general argument is presented against relativistic, unitary, single-outcome quantum mechanics. This is achieved by combining the Wigner's Friend thought experiment with measurements on a Greenberger-Horne-Zeilinger (GHZ) state, and describing the evolution of the quantum state in various inertial frames. Assuming unitary quantum mechanics and single outcomes, the result is that the Born rule must be violated in some inertial frame: in that frame, outcomes are obtained for which no corresponding term exists in the pre-measurement wavefunction

The Case against Factorism

We discuss the case against Factorism, which is the standard assumption in quantum mechanics that the labels of the ⊗-factor Hilbert-spaces in direct-product Hilbert-spaces of composite physical systems of similar particles refer to particles, either directly or descriptively. We distinguish different versions of Factorism and argue for their truth or falsehood. In particular, by introducing the concepts of snapshot Hilbert-space and Schrödinger- movie, we demonstrate that there are Hilbert-spaces and ⊗-factorisations where the labels do refer, even descriptively, to similar particles, which renders them probabilistically absolutely discernibl