Understanding Popper's Experiment

An experiment proposed by Karl Popper is considered by many to be a crucial test of quantum mechanics. Although many loopholes in the original proposal have been pointed out, they are not crucial to the test. We use only the standard interpretation of quantum mechanics to point out what is fundamentally wrong with the proposal, and demonstrate that Popper's basic premise was faulty.Comment: Edited version, to appear in Am. J. Phy

Mechanically reclaiming abandoned saline soils: a numerical evaluation

Water quality / Groundwater / Simulation models / Calibrations / Water table / Water balance / Hydraulics / Soil reclamation / Soil water / Flow / Soil properties / Salinity / Pakistan / Punjab / Sindh

Twisted Poincar\'e Invariant Quantum Field Theories

It is by now well known that the Poincar\'e group acts on the Moyal plane with a twisted coproduct. Poincar\'e invariant classical field theories can be formulated for this twisted coproduct. In this paper we systematically study such a twisted Poincar\'e action in quantum theories on the Moyal plane. We develop quantum field theories invariant under the twisted action from the representations of the Poincar\'e group, ensuring also the invariance of the S-matrix under the twisted action of the group . A significant new contribution here is the construction of the Poincar\'e generators using quantum fields.Comment: 17 pages, JHEP styl