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## Full-Text Articles in Physics

Logic Is To The Quantum As Geometry Is To Gravity, Rafael D. Sorkin

#### Logic Is To The Quantum As Geometry Is To Gravity, Rafael D. Sorkin

*Physics*

will propose that the reality to which the quantum formalism implicitly refers is a kind of generalized history, the word history having here the same meaning as in the phrase sum-over-histories. This proposal confers a certain independence on the concept of event, and it modifies the rules of inference concerning events in order to resolve a contradiction between the idea of reality as a single history and the principle that events of zero measure cannot happen (the Kochen-Specker paradox being a classic expression of this contradiction). The so-called measurement problem is then solved if macroscopic events satisfy classical rules of ...

Feasibility Of Measuring The Shapiro Time Delay Over Meter-Scale Distances, Stefan Ballmer, S. Marka, P. Shawhan

#### Feasibility Of Measuring The Shapiro Time Delay Over Meter-Scale Distances, Stefan Ballmer, S. Marka, P. Shawhan

*Physics*

The time delay of light as it passes by a massive object, first calculated by Shapiro in 1964, is a hallmark of the curvature of space-time. To date, all measurements of the Shapiro time delay have been made over solar-system distance scales. We show that the new generation of kilometer-scale laser interferometers being constructed as gravitational wave detectors, in particular Advanced LIGO, will in principle be sensitive enough to measure variations in the Shapiro time delay produced by a suitably designed rotating object placed near the laser beam. We show that such an apparatus is feasible (though not easy) to ...

Is The Spacetime Metric Euclidean Rather Than Lorentzian?, Rafael D. Sorkin

#### Is The Spacetime Metric Euclidean Rather Than Lorentzian?, Rafael D. Sorkin

*Physics*

My answer to the question in the title is "No". In support of this point of view, we analyze some examples of saddle-point methods, especially as applied to quantum "tunneling" in nonrelativistic particle mechanics and in cosmology. Along the way we explore some of the interrelationships among different ways of thinking about path-integrals and saddle-point approximations to them.