A. Shimony | Searcharxiv

arXiv2022

Determining the Self-Similar Stage of the Rayleigh-Taylor Instability via LLNL's NIF Discovery Science Experiments

We report a novel measurement of the late time self-similar growth constant $\alpha_B$ of the Rayleigh-Taylor instability (RTI) from controlled initial perturbations. To this end, we have developed a laser-driven experiment, fielded on the National Ignition Facility (NIF), to explore deeply non-linear, multimode hydrodynamic growth of a planar interface. The measured value is $\alpha_B=0.038\pm 0.008$, which is consistent with previously reported 2D simulations and closer to previously reported 3D simulations. This resolved the known discrepancy between experiments and simulations of RTI.

physics.flu-dyn↗

arXiv2001

The Depth and Breadth of John Bell's Physics

John Bell's investigations in foundations of quantum mechanics, particle physics, and quantum field theory are recalled.

physics.hist-ph↗

arXiv1996

Insolubility of the Quantum Measurement Problem for Unsharp Observables

The quantum mechanical measurement problem is the difficulty of dealing with the indefiniteness of the pointer observable at the conclusion of a measurement process governed by unitary quantum dynamics. There has been hope to solve this problem by eliminating idealizations from the characterization of measurement. We state and prove two `insolubility theorems' that disappoint this hope. In both the initial state of the apparatus is taken to be mixed rather than pure, and the correlation of the object observable and the pointer observable is allowed to be imperfect. In the {\it insolubility theorem for sharp observables}, which is only a modest extension of previous results, the object observable is taken to be an arbitrary projection valued measure. In the {\it insolubility theorem for unsharp observables}, which is essentially new, the object observable is taken to be a positive operator v alued measure. Both theorems show that the measurement problem is not the consequence of neglecting the ever-present imperfections of actual measurements.

quant-ph↗